4AGE: I need help on cooling system

[coryflying]

I recently bought an '87, as I was driving it home it began to overheat. So far I've tied bleeding the system ( it got better would run hot and cool down-run hot then cool down) I pulled the thermastat- it runs normal until steam is forced into the overflow tank.Could this be a water pump or a head gasket? Is there any way to check the pump? There is no water in the oil.

[88-4age]

i have a 1988 toyota mr2 with a 4AGE and i cant figure out why mine does it but i figured out that if you have a decent amount of water in the main raditor line that it stays pretty cool

[dirocyn]

Probably some air in a coolant line somewhere. Follow the directions in the BGB for getting the air out of your system, and good luck.

[tjmr2]

Air in the head, radiator and or heater and the long lines that transverse the car from front to rear can cause lack of coolant flow and hot spots that will overheat spots in your engine and over heat it, sooner than you can get to Denial.

Read the BGB and follow it's recommendations to the letter as a minimum or more. I use a brake bleeder with a 1 Qt canister in front of the vacuum brake bleeder reservoir and bleed at least 2 quarts thru each the heater and radiator to make sure all the air is out. It's clean fluid so you can add it back in at the filler neck, but you get all the air out.

Good luck!

[te51levin]

You definitely want a thermostat installed. Use a Toyota thermostat if at all possible. They cost about $14 through me. The aftermarket ones (Stant, etc) just don't seem to be very high quality. Once you get the 'stat installed, bleed the coolant using the procedure in the BGB - clear hose on radiator & heater bleed valves (free end elevated), all valves open, heater control set to HOT. I like to run the engine while bleeding it to make sure that coolant can circulate through the entire system and push out any pockets of air. Keep topping the system off at the filler neck until there are no longer any air bubbles escaping from anything, then shut all the bleeders and install a filler cap (preferably new and preferably OEM Toyota).

[razor1]

Is the heater bleed valve near the master cylinder? Any pics available?

[muffinman]

Originally Posted by razor1

Is the heater bleed valve near the master cylinder? Any pics available?

[SeeTopher]

Maybe its just the radiator cap. I had the same problem. I bled the system and change thermostat. But nothing worked until I replaced the radiator cap. The problem was fixed. But don't get me wrong it doesn't hurt to change these parts anyways.

[razor1]

thanks muffinman, I looked again this morning and finally spotted it, so I'll be bleeding the system later this week.

[asj]

...

[te51levin]

Originally Posted by asj

... there's another way of doing it. Back the car, up an old pair of ramps. Get the back end up, nice and high, almost touching the front air dam. Then, do a conventional drain and fill.

And, brrrrrrp! out comes all the air.

Kind of like burping a baby. Works every time. Saves you going to an awful lot of trouble. Fair warning: Don't use cheap coolant. You'll regret it. The stuff you want, is genuine Toyota coolant.


Best,
~ Sammy, '88 Supercharged

I don't think I'd trust that as an acceptable substitute for the factory procedure. This method does not change the fact that the radiator and heater core remain high spots.

It's not difficult to use the car's bleed ports at the heater core and radiator, and that WILL get the air out.

[razor1]

I bled the system today (3 bleeders open, 2 with hoses attached, heat on, adding fluid until it wouldn't take any more) it ran for about 30 mins...revved it a few times and the temp gauge stayed in the middle (normal range) Tightened the radiator cap, took it for a spin and within 10 mins temp gauge in the red but no steam, bubbling or over flow. The radiator felt warm but not hot, the hoses under the hood felt a little hot but not extreme. Could the gauge be wrong? I did replace the gauge temp sender too. Any ideas?

[te51levin]

Originally Posted by razor1

Tightened the radiator cap, took it for a spin and within 10 mins temp gauge in the red but no steam, bubbling or over flow.

And the car has a new, OEM Toyota (in a Toyota box from a Toyota dealership) thermostat? If not, that is the next step.

Originally Posted by razor1

The radiator felt warm but not hot, the hoses under the hood felt a little hot but not extreme. Could the gauge be wrong?

Yes, it could. More often it's the sender at fault rather than the gauge. Get a hold of an infrared thermometer and see what the water temperatures really are around the system with the gauge indicating "normal" (about halfway up the scale) and hot. It is possible that your gauge is simply not reporting the truth.

[d.vanheeckeren]

could you by chance take a picture of where the thermostat is located? I took what I thought was the housing off (right above the alternator) and was surprised to find that it's WAY to small for the thermostat. I have no idea where to look next. I have a suspicion that it's right under the battery, but it has several cooling system hoses and a few vacuum hoses attached to it, too, so I'm not really sure. Am I wrong?

[muffinman]

Originally Posted by d.vanheeckeren

could you by chance take a picture of where the thermostat is located? I took what I thought was the housing off (right above the radiator) and was surprised to find that it's WAY to small for the thermostat. I have no idea where to look next. I have a suspicion that it's right under the battery, but it has several cooling system hoses and a few vacuum hoses attached to it, too, so I'm not really sure. Am I wrong?

That's it. Mounted to the top of the trans almost below the battery with the coolant and vac hoses.

[te51levin]

Originally Posted by d.vanheeckeren

I have no idea where to look next.

Please don't take this personally - this goes for everyone, but especially for the MkI owners on this forum, who, as a group, seem largely unwilling to buy or read a book.

If you are going to work on your own car, you need a shop manual.

They do not have to be expensive.

Amazon.com: Toyota MR2, 1985-1987: All Models...



The internet is wonderful, but a little more self-sufficiency would benefit individuals here as well as the group in general. Just taking parts off until you find what you are looking for is a waste of time, both for the person with the problem and for others trying to help.

There is absolutely no excuse for not having some sort of repair manual!

[muffinman]

Originally Posted by te51levin

There is absolutely no excuse for not having some sort of repair manual!

+1

The BGB download is free and will help you with pretty much everything you will need.

[d.vanheeckeren]

Well, honestly, I'm not familiar with this car. I got it about a month ago with plans to restore it. I was sure it was above the alternator (from all other cars I'd worked on), otherwise I wouldn't have started there.
I did look for a manual locally, but needed one right away, which is why I didn't order one. I did download the service repair manual for that car from teq.org: MK1 AND MK2 BGB/EPC MANUALS, but it included only drawings and didn't label where the thermostat was. I'm the kind of person that prefers to ask before breaking things, and since the BGB wasn't very clear to me, I asked instead. :o)
No offense meant, just letting you know that with my time constraints and lack of clarity in the manual, I decided to see if someone else knew.

[muffinman]

Originally Posted by d.vanheeckeren

No offense meant, just letting you know that with my time constraints and lack of clarity in the manual, I decided to see if someone else knew.

I'm not offended in any way.

If your not sure it's always better to ask then just guess. The Haynes manual is a pretty good book to get if you plan on working on the car yourself though.

I've noticed that Aaron's been a little grumpy lately so don't take it the wrong way. He's a very nice guy and knows all the ins and outs of these cars.

[te51levin]

Originally Posted by d.vanheeckeren

No offense meant, just letting you know that with my time constraints and lack of clarity in the manual, I decided to see if someone else knew.

I understand, and that's why I didn't mean my suggestion as a personal slam of any kind. Lately it seems that not many people are doing any research at all, and are not making any effort at all to find their own information. There's a lot of information already out there and most of it is not hard to find.

There is nothing wrong with asking for help, but there's a point at which those who can help get tired and lose interest. A lot of the "been there, done that" guys who have solid answers don't come around anymore, and many others who jump in with comments frankly don't know what they are talking about. Result: those who need assistance get lower quality help, or no help at all, and the forums become less worthwhile overall.

Originally Posted by muffinman

I've noticed that Aaron's been a little grumpy lately so don't take it the wrong way.

Absolutely true, and I apologize for that, but it's exceptionally frustrating seeing the overall lack of effort being put forth lately.

Again, that's not directed at any individual at this thread. It is a general comment on the current atmosphere in the MkI camp as a whole.