Hi. I'm working on my son-in-law's TE V6 3 litre. He has either a blown head gasket or cracked head. I'm wondering if I really have to remove the crankshaft pulley and lower timing belt cover to remove the heads? The Max Ellery workshop manual says I do, but sometimes the books take the 'long way around'.

It looks like the only way to get the lower cover off (to loosen the belt) is to remove the balancer. Is that correct? I dont want to remove the timing belt, I just want to loosen it. (And I dont have a pulley remover so I'm trying to avoid that problem).

(I did the heads on my Pajero not long ago. I didn't have to remove the pulley for that. The cover comes off without having to remove the pulley).

Any suggestions appreciated.

(I did the heads on my Pajero not long ago. I didn't have to remove the pulley for that. The cover comes off without having to remove the pulley).

Any suggestions appreciated.

How do you do the heads on a Pajero without removing the cam belt, crank pulley, timing covers etc?
What did you actually do to the Pajero heads?

For a Magna V6 head to come off, you need to remove the cam belt, no way around that. Anyway, once the crank bolt is off, the crank pulley just slips off. No puller required.
It's impossible to just loosen the belt a bit and get the tension right when you put it all back together, anyway.

How do you do the heads on a Pajero without removing the cam belt, crank pulley, timing covers etc?
What did you actually do to the Pajero heads?

For a Magna V6 head to come off, you need to remove the cam belt, no way around that. Anyway, once the crank bolt is off, the crank pulley just slips off. No puller required.
It's impossible to just loosen the belt a bit and get the tension right when you put it all back together, anyway.

On the Pajero the timing cover can be removed without removing the pulley. The cover does not go all the way around the crank like it does on the Magna. So I just removed the cover and loosened the timing belt. I had a blown head gasket (at 310,000ks) so I removed both heads, had some minor head repairs done, replaced the stem seals, and reinstalled them with a full gasket set.

The Paj and Magna motors are very similar, thats why I was a little surprised its harder to get the cover off the Magna motor. Anyway it looks like the pulley has to come off.

By the way.. Whats the situation with posting pictures on this forum? It seems that some threads have pics but most don't. I cant post pics.

Have you done a hydrocarbon test of the coolant?

Have you done a hydrocarbon test of the coolant?


No, what will that tell me?

It identifies that there are combustion gasses entering your cooling system.

They show up by measuring the hydrocarbon content(i.e. burnt petrol aka hydrocarbons) of the coolant/water mix.

In a healthy engine, the reading should be 0%.

If you already know for certain that you have a blown head gasket/cracked head, I'm not sure it will be of benefit to you.

It's just really a 'short cut' instead of having to do a compression test and/or leakdown test(pressurising the cooling system via the radiator cap and seeing if the pressure drops- once again just identifying that there is a pathway between cooling system and combustion chambers that should not be there).

The following video is not the best, but it might give you some idea as to how a hydrocarbon test is done..


https://www.youtube.com/watch?v=vG2XOXlItaA

It's just a chemical test to confirm you definitely have a cracked head or blown head gasket by checking the coolant for hydrocarbon (oil and fuel).

Air bubbles in the coolant or a cooling system which is not holding pressure are not definitive tests.

Good luck!

I have no doubt a gasket is blown. Possibly a cracked head too. The thing blows its top after only about 10 minutes. Its been doing it for quite a while but its a second car and was only used for short local trips so it wasnt much of a worry. Son-in-law threw in some stop leak which helped marginally for a while. Might not be worth fixing once I get the heads off. We'll see.

...

By the way.. Whats the situation with posting pictures on this forum? It seems that some threads have pics but most don't. I cant post pics.

You have to become a member (free) at a site like www.photobucket.com
You then can upload pictures from your computer into your photobucket account.
Once uploaded there will be a img link underneath them which you can copy and paste into threads and the pictures will show

You have to become a member (free) at a site like www.photobucket.com
You then can upload pictures from your computer into your photobucket account.
Once uploaded there will be a img link underneath them which you can copy and paste into threads and the pictures will show

Why is it done like that? Most forums I am in can attach pics directly into the post. Its a lot easier. Obviously not many people can be bothered using photobucket here. A forum with pics would be a lot more popular and helpful I think.

Photobucket allows you to drag and drop so it's fairly easy to use.
Though the option of uploading straight to the forum would be nice

Why not just get another motor? Chances are it will end up being cheaper than fixing yours and you could even upgrade to one of the bigger ones.

Resident guru Madmagna (his business Mitsfix) should be able to sort you out with the correct gasket.

He says problems with the metal head gaskets are quite rare. In another thread I read he said it's probably more likely an actual crack in the head rather than the gasket because they are that good.

Give him a buzz.

I would get rid of the car.

I would get rid of the car.

Yeah that might still happen. It depends on the condition of the heads when I get them off. If i can get away with just a couple of head gaskets then it will be worth fixing. The rest of the car is quite good apart from peeling paint. It still rides pretty nicely and auto tranny is smooth. But if the heads need work then it will probably be scrapped.

What model Pajero, this makes a world of difference.

As for the magna, dont waste your $$ on doing a head, just replace the motor. It is so unusual to blow a head gasket on a S4 motor and if this is the case then the bottom end will have been cooked as well thus is pretty much useless

As for the pics, because hosting and bandwith cost money

What model Pajero, this makes a world of difference.

As for the magna, dont waste your $$ on doing a head, just replace the motor. It is so unusual to blow a head gasket on a S4 motor and if this is the case then the bottom end will have been cooked as well thus is pretty much useless

As for the pics, because hosting and bandwith cost money

The Pajero is a '91 NH V6 3 litre 12 valve. I blew a head gasket on that a year or two ago. Blown head gaskets are not uncommon on those motors, why would the Magna 3.0 litre be different? Its a very similar motor.

why would the Magna 3.0 litre be different? Its a very similar motor.

I've been inside both motors, and trust me, they are worlds apart.
The 12 valve 3.0L has a cam belt with tension initially adjusted by a spring, whereas the 24 valve has a hydraulic tensioner which continuously adjusts the belt tension. Hence what you did on the 12 valve Pajero motor can't be done on the 24 valve Magna motor.

OK, the heads are off. As Madmax predicted the gaskets look fine. (They are 100% metal sheets, unlike the Pajero gaskets which were some kind of compressible composite. This was an interesting development considering that they are the same family of engines.)

I cant see any obvious cracks in the head that would cause the rapid overheating but I guess they can be pretty hard to see. In fact the heads look pretty good, but I will look closer tomorrow. Anyone had a cracked Magna head? Can you describe where the crack was? I'm guessing only a head shop can really confirm that it is OK.

Never cracked a Magna head, but did on a Toyota Crown many years ago. Made a HUGE cloud of steam, killed one cylinder and ran out of coolant in about 10 minutes (luckily I was 8 minutes from home!). In that case the crack was right at the peak of the combustion chamber between the valves, I can't recall which cylinder. It was virtually invisible to me, took it to a head shop who cleaned it up and spotted it. Considering the speed the coolant blew out I was expecting a huge crack, this was maybe 3-4mm long and a hair's-width wide. It would have been weld-able but the rest of the head was pretty much Swiss cheese, a previous owner clearly didn't know much about alloy heads and ran water as a coolant for most if its life :facepalm. Your best best is to get them checked out by the pros, now that they are already off the motor.

PS: Have you eliminated other causes of rapid overheat, such as a stuck-shut thermostat or stuffed water pump? In my (limited) experience a cracked head or blown gasket generally reveals itself in other ways than just overheating, such as the coolant going somewhere it shouldn't like the exhaust system (steam), oil galleries (white muck in the oil) or external (steam + water dripping), or gasses blowing into the coolant (exhaust gasses bubbling up through the radiator).

Thanks Ensonig5. Thats exactly what I wanted to hear. I Googled for info about cracked heads and most showed cracks between the valves, but it puzzled me if such cracks could cause the overheating that we experienced. You've confirmed that it does. So tomorrow I'll be cleaning them up and looking closer between the valves.

We removed the thermostat a month ago. It didnt really make any difference. Rapid boiling continued. Eventually the radiator split too. Time to fix it or ditch it we decided.

We removed the thermostat a month ago. It didnt really make any difference.

You did what now?

That's not a good idea on a third gen Magna! What you have effectively done is prevent any coolant from reaching the radiator because the thermostat is different to just a traditional one. You need to google coolant bypass circuit thermostat.

That will make it infinitely worse, not better.

I doubt you ever had a cracked head... Although you might well have one now after driving without the thermostat.

That's why I suggested a hydrocarbon test before pulling the heads.

The Pajero is a '91 NH V6 3 litre 12 valve. I blew a head gasket on that a year or two ago. Blown head gaskets are not uncommon on those motors, why would the Magna 3.0 litre be different? Its a very similar motor.

You are talking about 2 totally different engines here, 2 totally time periods and 2 totally different mechanical set ups

The 6G72 in your Pajero was a 6G72 S2. The 6G72 in your Magna is a 6G72 S4. The old Pajero had different everything.

To remove heads because you have over heating issues is foolish to say the least. Until you are able to confirm if a head gasket is blown and which one you don't touch heads, especially when everyone is telling you how rare this can be

A bad Thermostat, blocked radiator, faulty water pump, non working fans are just a few of the many reasons a car can overheat.

Now above you state you removed the thermostat and is over heating. No shit shirlock, you have just removed the only part of the system which will allow coolant to FLOW THROUGH THE RADIATOR.........Magna's CAN NOT run without thermostats as they have a bypass so when the motor is cold it bypasses the radiator to allow faster warm up, fluid will take the path of least resistance. In some cars it will also cause coolant to flow too fast through a radiator and not cool.

Your son put stop leak in the cooling system, take the heads down to a metal scrapper and get your 10 bucks for them as they are now worthless. The cracks, if any (and I have rarely seen a S4 head crack, many S2 heads do but not S4) will now be sealed up and nigh impossible to detect.

As I said earlier, just replace the motor, check the cooling system and actually diagnose the issue instead of wasting your and everyone elses time by pulling off parts which most likely are not the issue

You did what now?

That's not a good idea on a third gen Magna! What you have effectively done is prevent any coolant from reaching the radiator because the thermostat is different to just a traditional one. You need to google coolant bypass circuit thermostat.

That will make it infinitely worse, not better.

I doubt you ever had a cracked head... Although you might well have one now after driving without the thermostat.

That's why I suggested a hydrocarbon test before pulling the heads.

I understand the bypass method. The car was boiling wildly before we pulled the thermostat. We took it out. Tested it in boiling water. It seemed to be fine. We ran the car for a while without it anyway to see if it made any difference. It didn't. The car boiled just the same. I doubt we have have done any further damage. It hasnt been run much without it.

I understand the bypass method.

You wouldn't have run the car with the thermostat removed if you did.

If the car is running hot and boiling because of a blocked radiator, all you've done is stopped what little flow was going the radiator and opened the path of least resistance - which is recirculating coolant straight back into the engine - and made it worse.

Methinks you probably had a pretty simple problem on your hands - faulty thermostat (yes they can test fine in boiling water but still be faulty), blocked radiator, failed water pump or even as simple as radiator cap.

You really should ring Mitsfix.

In some cars it will also cause coolant to flow too fast through a radiator and not cool.

Unbelievable!.... You are a mechanic and you repeat that utter nonsense!

But the rest of the points you made were all considered at the time. Surely you dont think that the decision to pull off the heads was taken lightly. As best as I was able I checked radiator and water flow. Putting in stop leak was a second-to-last resort. The key symptom however was that the car continued to boil really quickly.

Maybe don't ring Mal.

As probably the most reputable and knowledgable Magna and 380 guy in the country, he couldn't possibly help you :nuts:

You wouldn't have run the car with the thermostat removed if you did.

If the car is running hot and boiling because of a blocked radiator, all you've done is stopped what little flow was going the radiator and opened the path of least resistance - which is recirculating coolant straight back into the engine - and made it worse.

Methinks you probably had a pretty simple problem on your hands - faulty thermostat (yes they can test fine in boiling water but still be faulty), blocked radiator, failed water pump or even as simple as radiator cap.

You really should ring Mitsfix.

My aim was to see if it made any difference to how rapidly it boiled. It didnt. The car boiled fast, but no faster. After checking everything else as best as I could I determined a crack or gasket was the problem. It wasnt a hasty decision.

There's no need to justify your process of fault finding or your decision to fix or junk the car.

There are a few people on this forum who think there are only 2 ways of fixing a car, their way or the wrong way.
Once one voice of criticism pops up, a lot of others jump on the same bandwagon as well.

With the head off, I'd be looking for - besides the obvious one, cracking between valve seats - loose valve guides. Not common on these engines, but it is one possible source of cylinder compression escaping into the cooling passages and pressurising the cooling system to the point of rapid overflow.

You may also want to pull off the water pump and check the vanes for corrosion.

Good luck with the fix.

Unbelievable!.... You are a mechanic and you repeat that utter nonsense!

But the rest of the points you made were all considered at the time. Surely you dont think that the decision to pull off the heads was taken lightly. As best as I was able I checked radiator and water flow. Putting in stop leak was a second-to-last resort. The key symptom however was that the car continued to boil really quickly.

Yes I am a Mechanic, the only utter nonsense is the utter crap and dribble you have posted in this thread. You clearly have less knowledge about cars than a 2 year old does about rocket science and when people who have experience advise you this is the best you can come up with. You sir are an idiot. Yes I have had cars over the years where the thermostat has been removed get hot under load because the cooling system is flowing too fast through a high flowing radiator, it can happen. Not to a Magna, you have a situation where there is no flow

Do us all a favour, and do the car a favour and scrap it like you initially hinted as clearly you will not listen to a specialist in these cars, hell you think an old 12v motor is the same as the 24v motor, shows your knowledge or lack there of.

Last resort, you criticise me about my knowledge and you dont even know what a monoxide test is, you dont do any tests other than "she gets hot real quick), seriously? So many causes for over heating but yes, here is another, google wave spring as I am sure you will blame that next.....

Can I please recap a few things....

With flakey paint and old age this car was worth about $300 at most. With a boiling engine it wasn't even worth that. The choices were to fix it VERY cheaply or not at all. The option of fitting another engine as suggested by Madmagna was never going to happen. It wasnt worth it in my opinion and I don't have suitable facilities to do that easily anyway.

All 'free' DIY methods of detecting the cause of the overheating were tried. I dunno what else I could have done. As mentioned above, expensive testing options (or any professional help for that matter) were 'not on'. Ultimately I concluded it was a head gasket or cracked head.

My comments about the Pajero engine Vs the Magna engine were just comments in passing. I was just asking questions or mentioning interesting points of difference. I wasn't insisting on anything or arguing anything.

Madmagnas comment that head gaskets rarely fail was accepted and as I mentioned earlier he appears to be correct. I read his comments before I removed the head but proceeded anyway. What else could i do considering my earlier comments re the value of this car? Ultimately I had to know if the head was cracked or not.

Trying stop-leak and seeing what happened when the thermostat was removed were last resorts. Removing the thermostat made no difference. It caused the car to boil NO FASTER. This suggested to me that the overheating was not a cooling system problem. I also decided that the minimal amount of driving proposed with the thermostat removed would not be detrimental to the car. (Just 1 or 2 kms to the shop and back). Under normal circumstances the car would have barely warmed up over these distances.

My statement regarding Madmagna's 'utter nonsense' only concerned this particular comment of his...

"In some cars it will also cause coolant to flow too fast through a radiator and not cool".

That is a total myth and has been debated in many motoring forums. It defies all rules of heat transfer. I'm not going to expand on it here. You can google numerous discussions about it yourself. Heres one...
http://www.badasscars.com/index.cfm/page/ptype=product/product_id=280/category_id=13/mode=prod/prd280.htm


Apart from that, all is cool.

(edit . The myth above just concerns 'heat transfer'. Not to be confused with bypass thermostats that also change the direction of the water flow).

Well I am sorry, you can pull up any internet page but as a mechanic I can say I have seen it happen, a has one of my mechanics here who spent many years as an engine reconditioner. It was an example of what can happen in some situations.

I have also seen magna's with over heating issues from partly blocked radiators, have seen them with overheating issues because too much coolant was used, thin it out and all good. AU falcons are well known for this. And as for defying rules of heat transfer, bullshit is all I can say

At the end of the day you are totally flawed on your reasoning. Removal of heads and then getting them surfaced, tested etc and then gasket kits on top of that will cost much more than a reasonable cheap second hand engine.

Hey is your car, do as you wish. Was trying to assist you, will not be making that mistake again that is for sure. All the luck in the world sir as you will need it.

Removal of heads and then getting them surfaced, tested etc and then gasket kits on top of that will cost much more than a reasonable cheap second hand engine.



I don't have a wrecking yard, a fully equipped workshop, or (by choice) the budget at my disposal to make that a viable option. But I do have a fair degree of spare time available and I like to tinker so doing it 'my way' doesn't seem unreasonable. I can easily put it back together again. Whats the worst it can do... overheat? Oh thats right...

Had a quick look at the heads today. Cant see any cracks around the valves but I probably need to give it a much better cleanup to see those if thats at all possible.

Something that did surprise me a bit was the corrosion on the outside water jackets of cylinder no3 on the engine BLOCK. (Thats the rear centre cylinder.) Theres only 5mm of metal between the jacket and the bore. That means theres only 5mm of metal gasket keeping the water and the hot compressed gases apart. I cant see any evidence of cross-leakage at this point but I don't know if it would show anyway. All the other jackets have 7mm or more of metal between the jacket and the bore.

Anyone else got a block lying around that they can measure? I'd like to know if this minimal amount of metal is 'normal'.

There's no need to justify your process of fault finding or your decision to fix or junk the car.

There are a few people on this forum who think there are only 2 ways of fixing a car, their way or the wrong way.
Once one voice of criticism pops up, a lot of others jump on the same bandwagon as well.

With the head off, I'd be looking for - besides the obvious one, cracking between valve seats - loose valve guides. Not common on these engines, but it is one possible source of cylinder compression escaping into the cooling passages and pressurising the cooling system to the point of rapid overflow.

You may also want to pull off the water pump and check the vanes for corrosion.

Good luck with the fix.

I can't believe it, but I am agreeing with you....the guy is having fun with a car that's basically junk.

I can't believe it, but I am agreeing with you....the guy is having fun with a car that's basically junk.

Hooray, someone gets it!! This ain't a Ferrari I'm dicking around with. Its a near 20 year old Magna that has barely moved for 3 months. Son-in-law is probably hoping I CAN'T fix it. He'd be happy to have an excuse to buy another car. And even at my age I still like to learn stuff. Been playing with cars for 45 years but never taken a Magna donk apart before. I might learn something useful to keep my 350,000 km TF on the road. I might even wind up with an auto tranny to experiment with. Then I can start giving advice about wave springs and stuff. That should really rattle Madmagna's chain. Ha!

Something that did surprise me a bit was the corrosion on the outside water jackets of cylinder no3 on the engine BLOCK. (Thats the rear centre cylinder.) Theres only 5mm of metal between the jacket and the bore. That means theres only 5mm of metal gasket keeping the water and the hot compressed gases apart. I cant see any evidence of cross-leakage at this point but I don't know if it would show anyway. All the other jackets have 7mm or more of metal between the jacket and the bore.


Check the block, head and head gasket at that point for signs of heat discolouration. If that is where exhaust gases have been going, you may see signs of it.
Check the block and head at that spot for flatness.

If you think it is worth the money, get the heads pressure tested and if ok, resurfaced.

Check the block, head and head gasket at that point for signs of heat discolouration. If that is where exhaust gases have been going, you may see signs of it.
Check the block and head at that spot for flatness.

If you think it is worth the money, get the heads pressure tested and if ok, resurfaced.

I shall check whatever I can tomorrow. Whether to pressure test or not will be up to son-in-law. Any idea how much a pressure test costs?