Overheating Nightmare !!

[supranut]

My 88 MK3 NA just keeps overheating no matter what my mechanic does to fix it. A new head gasket when I purchased the car in November. I knew that when I bought it dirt cheap. The last six weeks or so I have had the rad changed, put in an electric fan with a high output fan with a sensor to regulate when the fan comes on. A new rad cap and themostat of course. A new Fram oil filter and battery yesterday just in case. A pressure test on the cylinders a pressure test on the cooling system no leaks on each test. Did a dye test had one leak causing bubbles in the rad fixed the bubbles. If I drive 100km only I can drive about 50km without overheating but when I check the coolant level I need about a litre to top it up. Coolant has come out through the overflow. If I drive more than 120 then I can only go about 20-25 km and the temp gauge goes almost all the way up, this is with the A/C on full blast. If I drive without the A/C on I can drive maybe an extra 20 kms. When the dye test was done he looked in the cylinders to see if any dye was present inside the cylinders and there was none present. All the hoses were taken off to see if there was any blockage and there was no blockage. The car can idle forever without overheating even a little bit. I'm going crazy, my mechanic is going crazy. If anyone can give any suggestions I would really appreciate it. I'm using my mechanics car for a week long fishing trip tomorrow so if anyone suggests anything today on this board I'll suggest it to him before I go. If not when I come back next week hopefully your suggestions will help fix the problem if he hasn't found it by the time I get back. Thanks everyone in advance for all suggestions this is a great board for problem solving. Have a great day.....TT

 

[SupraMario]

that really sounds like BHG. did ur machanic torque the head to 75lbs or toyotas 57?

 

[supranut]

I really don't know what he torqued the bolts to but there are not any oil leaks that we can see. He feels that it cannot be the head gasket due to no bubbles or oil in the coolant, no dye in the cylinders etc. Thanks for the reply keep them coming if you could please.....TT

 

[Maroon88]

Here are a few things to check:

Make sure the impeller on the waterpump still has all the vanes. Some are aluminum and others are steel so they may have corroded and you have little to nothing moving the water through the engine.

Make sure there is nothing blocking the airflow through the AC condensor and the radiator.

Make sure there isn't any blockages in the head or block keeping water from flowing through.

Make sure the new thermostat actually works. I have gotten bad thermostats several times.

 

[supranut]

Thanks Maroon 88 mine is maroon as well. I know he said he checked the water pump and said it was working great. I will mention all the things you have suggested. Keep those suggestions coming I really appreciate them.....TT

 

[SupraMario]

when it says its hot, can u go out and open the hood and do u hear and see the water boiling in the resivor?
if not check, maybe the gauge is messed up?

 

[supranut]

D34DC311 Oh Yaa! you can hear it boiling big time it's so hot I'm almost afraid to open the resevoir. There's no question about that. My tempeture gadge is my best friend right now if it wasn't for that my car might be toast.(lol) Thanks for the reply.....TT

 

[Supra Blues]

Here are a few things to check:

Make sure the impeller on the waterpump still has all the vanes. Some are aluminum and others are steel so they may have corroded and you have little to nothing moving the water through the engine.

Make sure there is nothing blocking the airflow through the AC condensor and the radiator.

Make sure there isn't any blockages in the head or block keeping water from flowing through.

Make sure the new thermostat actually works. I have gotten bad thermostats several times.

Start here.

I too have bought new T-stats that were bad. If it idles and no overheat but at speed it overheats I think you are having a problem with airflow to the radiator and/or water flow through the engine.

 

[supranut]

Thanks for the reply Supra Blues that's what I have right now the Supra Blues, I was really looking forward to taking my car for a great run up north for my holidays but that's life for now. I will definetly mention that to my mechanic. Thanks again keep those suggestions coming I'm feeling better you guys or girls are giving me hope......TT

 

[GrimJack]

Make sure the clutch on your clutch fan isn't dead. Make sure that your auxilary electric fans are plugged in and come on when the engine is hot and the key is on.

Do you have a fan shroud? Do you have an engine undercover? Have you done a block test as well as the dye test?

 

[supranut]

Grim Jack I know that he put in another clutch fan and checked it, he just put in the new electric fan in and there is a fan shroud. The undercover I had the first 6 inches cut off because it was falling and dragging. I don't know if he did a block test or not. He did a pressure test on the cylinders I don't know if it's the same thing or not. Thanks for the response......TT

 

[SupraMario]

under engine cover isnt causing this, i dont have one,
u say that it is boiling over, check the radiator, look at the front of it(the part that is facing the bumper) see if it is cloged with a ton of leaves or junk,
you say it doesnt over heat when idel correct? then it does when driving, this may be the cause, because the clutch fan can blow on it while the car isnt moving but when the car is in motion the air from the fan is blown on the engine, and the radiator relys on air from speed. (see where im going with this)
Just a thought tho.

 

[supranut]

Thanks D34DC311 but the fan is brand new I wish it was that easy. Thanks for the helpfull suggestion though.....TT

 

[GrimJack]

Block test is a good idea. If that comes back with a fail, you know the problem right away, no worries about any other tests. And if the engine was assembled to Toyota specs, with 58 foot pounds on the head bolts, there is a good possibility that you'll blow the head gasket sooner rather than later.

The dye test is usually pretty good as well, however, it is possible to blow the gasket between the water jacket and the outside atmosphere, and unless you were looking in the right place, you'd miss the dye in the engine compartment.

 

[supranut]

* GrimJack I'm assuming that the pressure test on the cylinders is not the same as a block test so I will mention this for sure to my mechanic and see what he says,he will have a week to try different ideas. Thanks for the replies...TT

 

[drunk_medic]

I've actually had this nightmare before...

..I am cruising around and look down. The coolant reservoir light it on and my temp gauge is spiking. Steam is coming from under the hood and I am freaking out. Then I wake up.

 

[supranut]

drunk-medic I hope you have a suggestion that goes with that post. This one unfortunately appears ever time I wake up.....TT

 

[bluemax]

Try changing the water pump to a new Toyota pump.
Sometimes the water pump vanes wear (even on rebuilt pumps) and causes vorticies (or how ever you spell it) which heats up the water. The faster you drive the hotter the coolant gets until the cooling system can't cool enough, then the water temp goes up.
But if you slow down, it should start to cool down.

 

[T701jz]

This brings back old memories. You have mentioned that u replace ur fan clutch to electric fan. Now i'm curious if that fan made to mount at the front of the radiator or at the back. I'm thinking ur blades are running at the wrong direction. have u tried running w/out a thermo?

 

[T701jz]

Is ur car auto? if it is disregard about the fan direction.