okay. tr 91 manual 4cyl.

cracked head > chemiwelded
thermostat not opening > ripped its guts out
leaky hose > replaced with garden hose

so iv done just about every dodgy fix in the book to try and get my car to stop overheating

AND YET

for some reason, after about 15 k's the temp needle keeps on climbing. BUT
let it stay up there for a while and all of the sudden the needle just drops back to normal operating temperature. again, after a few k's the same thing happens. strangest thing is, when it drops, it does so in about 2 seconds. water cant possibly cool that fast.

confused? so am i.

and suggestions would be GREATLY appreciated. because im about ready to roll this thing off a cliff and laugh as it falls

cheers, rob

Thermo fans??

Possibly a blockage somewhere? have you tried flushing both the block and the radiator?

Chemiweld and radiator stop leak are good ways to block up the system, i have heard that black pepper works tho :)

Consider also that your temperature sender, gauge or wiring are broken.

how new is the radiator cap

Mine's doing this as well (1993 TR 4-cyl), temperature needle climbed up to the Hot marker for about 1.5 seconds then dropped back down to half. Engine didn't physically feel that hot afterwards. Added a splash of coolant, hasn't done it since, but i'm still suspect of the radiator cap.

Strangely it didn't want to idle the next morning either. Cleaned a few terminals and connectors which seems to have resolved that issue as well. Will be keeping an eye on it.

I'm going on a limb here and say it an electrical issues,

Might be a bad, lose engine earth
Temperature sensor might me stuff


Got to remember the car gauges need a good connection to negative side of the battery :)

Might be an idea to add your own water temperature gauge to the car and check against your factory temperature gauge :)

okay. tr 91 manual 4cyl.

cracked head > chemiwelded
thermostat not opening > ripped its guts out
leaky hose > replaced with garden hose

so iv done just about every dodgy fix in the book to try and get my car to stop overheating

AND YET

for some reason, after about 15 k's the temp needle keeps on climbing. BUT
let it stay up there for a while and all of the sudden the needle just drops back to normal operating temperature. again, after a few k's the same thing happens. strangest thing is, when it drops, it does so in about 2 seconds. water cant possibly cool that fast.

confused? so am i.

and suggestions would be GREATLY appreciated. because im about ready to roll this thing off a cliff and laugh as it falls

cheers, rob

Not confused at all, you have blocked the radiator with chemiweld, you have ripped the guts out of the only part of the cooling system that can regulate the flow of coolant (or water in your case) not that any coolant or water can get thorugh the chemi weld and then you wonder why it is overheating, just excuse me while I pick myself up off the floor and change my pants as I think I just wet myself laughing

Before you look at thermo fans and things that may actually cost you a few bucks to fix, try fixing the obvious things first, if you have a cracked head the chemiweld may not fix this, if you are gettnig combustion gas into the cooling system, there goes the ability for the system to cool

Replace your mums garden hose for her and get the proper hose as nylon will last about a week before it cracks again

If your fans are not coming on may be a relay issue as is common, dont use a freaking paperclip to fix, test with another relay you know that works like headlight relay (you are using globes and not candles I gather :) ) and if fans work when engine is at temp you know there is the issue

Sorry for being blunt, then again no I am not as you can not complain about a car not working properly when you do that to it and I am also known for to the point :)

The crack in the head is probably opening up at a certain temperature, fix that first and clean out the cooling system, should be ok after that. Check that the fans come on as well.

Not confused at all, you have blocked the radiator with chemiweld, you have ripped the guts out of the only part of the cooling system that can regulate the flow of coolant (or water in your case) not that any coolant or water can get thorugh the chemi weld and then you wonder why it is overheating, just excuse me while I pick myself up off the floor and change my pants as I think I just wet myself laughing

Before you look at thermo fans and things that may actually cost you a few bucks to fix, try fixing the obvious things first, if you have a cracked head the chemiweld may not fix this, if you are gettnig combustion gas into the cooling system, there goes the ability for the system to cool

Replace your mums garden hose for her and get the proper hose as nylon will last about a week before it cracks again

If your fans are not coming on may be a relay issue as is common, dont use a freaking paperclip to fix, test with another relay you know that works like headlight relay (you are using globes and not candles I gather :) ) and if fans work when engine is at temp you know there is the issue

Sorry for being blunt, then again no I am not as you can not complain about a car not working properly when you do that to it and I am also known for to the point :)

cheers bro

re read my post and you will notice the actual issue I have is how can the gauge climb, but drop so rapidly.
the cars in the middle of nowhere, and the idea is i need to get it on the road to make it back to adelaide, i dont have access to normal supplies up there... so i went up there with a few items to get it home.
you dont need to be a dick about it mate, if you have an opinion about the car i would love to hear it. but thats all i want to hear tbh.

thankyou everyone else for your suggestions il give them a try, but unfortunately it sounds like this is a dead motorcar

May have been an idea then to state that the car is up in the bush and you are tring to get the car home, you also need to understand that many post up dodgy repairs and wonder why they dont work

You want a suggestion, take a thermomiter up to the car or an external independant temp guage, this will tell you what is going on, if you are really getting heat or electrical issues, then you will have something to go by but remember if you are getting hot gasses seep by into the cooling system, the temp sensor is reading the temp of those hot gasis which initially are over 800deg and will generally get stuck along the way up to the highest point being the top rad tank

I did not mean to offend, was just stating fact and also, be careful about calling people dicks on forums as some will get really offended, I DGAF but some will have a real cry.

May have been an idea then to state that the car is up in the bush and you are tring to get the car home, you also need to understand that many post up dodgy repairs and wonder why they dont work

You want a suggestion, take a thermomiter up to the car or an external independant temp guage, this will tell you what is going on, if you are really getting heat or electrical issues, then you will have something to go by but remember if you are getting hot gasses seep by into the cooling system, the temp sensor is reading the temp of those hot gasis which initially are over 800deg and will generally get stuck along the way up to the highest point being the top rad tank

I did not mean to offend, was just stating fact and also, be careful about calling people dicks on forums as some will get really offended, I DGAF but some will have a real cry.

thankyou for your honesty. yeah i should have stated my intentions but this car is really stressing me out, i just need to somehow get it home so i can fix the head on it. either that or i cart up a torque wrench and head back up there... :/
il definately give this second thermometer a go, but i think you may be right about the gas, the system is under a shitload of pressure im assuming from the crack in the head so i may just have to invest in a few portable tools...

Did have the same issue with Mums TR, the waterpump belt snapped, it cooked and cracked the head. As a 'get her home' fix I put two bottles of chemiweld in it, and loosened the rad cap halfway so some pressure would release while still retaining some coolant. It did what your describing (temp gauge jumping) but nevertheless it made it 150 kays fine.
A tip i also did was Pull the A/C relay out, and then turn your ac on. both radiatior fans will kick in all the time (the car thinks your ac is on and compensates, but by removing the relay the ac clutch doesnt engage.)
Hope this helps

unfortunately the car is in Quorn (40k out of Pt Augusta) and i live in adelaide... thats about 400kms away :/ so im going to need a serious repair i think before i even attempt such a drive