My '87 auto n/a seems to hate thermostats - seems there's not enough coolant flow through the engine but it seems to be running a lot warmer than normal (not quite overheating) with a thermostat in. Is it reccommended to keep the thermostat in the car? If so, what's a good brand / temp. opening for it?

yes thermostat needed

and i think temps are 180deg

When I got mine at Advance they offered a 160, 180 and 190. I think then you might want to get the one that suits your climate, but like she said, you do need one or it will overheat. Check out your fan clutch too, it should be kind of slow to turn when cold, not free wheeling and the fans when the A/C is on.

Russ

Yep, replaced the fan clutch and water pump a few months ago; swapped out the thermostat at that same time but I think I got a faulty one. I decided to go with a Failsafe at 180. I live in Dallas, TX, so heat is definitely an issue.

Strange, though... w/o a thermostat in my car (I'd been running it that way for about a month) it never came even close to overheating except one time when I forgot to refill my coolant back to normal spec.

sounds very familiar to me

yes dd it is de ja vu,isn't it?.

Okay, added the thermo, overheated, shut down before it redlined.

Took thermo out, ran it, overheated, shut down before redlined.

No white smoke... no coolant in oil... no oil in coolant... no gurgling noises behind dash... though I'd been experiencing some coolant loss in the months past. I know my radiator drain plug gasket is shot, I'm leaking slowly via the heater hose on the back of the engine between the valve covers, leaking very slowly from two hoses off of the block itself. Day before last I'd run some block sealer / head gasket repair through the cooling system to seal it off... bad move. I think it may have clogged the cooling system. Problem is, it's my day-to-day driving car and I'm short on funds financially. Suggestions?

replace the head gasket

Take out the radiator and get it cleaned out. Before you put it back in, blow out the lines with clean water, open drain on side of engine. Pull the hose ends off the heater and flush that out too. There is a radiator flush you can try from the local part stores. Then fill it up with plain old water and try to find the tester for head gasket leak I have heard others talk about on this forum. That at least should let you know if the gasket is leaking.

It is amazing just how fragile the head gasket seems to be on these cars. The last quite a while stock but eventually they do start leaking, like all cars do. It is not always a blown head gasket when the engine starts to overheat. Water leaks, fans not working, fan clutch not working, etc. I still think the car needs a bigger radiator. I put one in mine and it works great and it has been over 100 each day for quite a while. I put an electric fan on it and I love it!

I have gutted the thermostats in a lot of my cars and they all ran too cool. It doesn't always work that way, but I thought the Supra would react the same way. You just can't have any air in the system with these cars either. Make sure your radiator cap is working right and allowing water from the purge tank to be sucked back in the system as it cools down.

Let us know how it works out. Driving in this heat is a pain in the ass with an overheating car. Too hot to run the heater...lol.

Russ

go to autozone and get the flush kit. it connects to your heater hose. you put in line of the heater hose and turn on your garden hose. it will flush whatever crap is clogging your system.
drive it.
if it keeps getting hot, check the summitracing.com for a radiator. call them if you like, just measure your radiator beforehand. keep in mind where the hoses go. they can sell you a universal aluminum radiator cheap, that you can install.
it will keep it way cooler.

i think i'm a cut to the chase kind of guy .
i plan on the worst and sometimes i get surprised .
hate to see you go through the agony of nickle and diming yourself thinking this "next" thing is going solve the problem

for now, every coolant leak has to be stopped or you will overheat for sure
try and get a replacement drain plug for the radiator
the specially formed hose for the back of the head costs too much u can use bulk hose from napa and loop it over to the heater valve . it might not look too pretty . but this is temporary like 3 bucks use 1 foot or so .
you have to stop all the leaks best as you can .

these leaks, more often than not , are symptoms not causes of over heating .
don't let the temp gauge go over 1/2 and start to think about how cool it would be to know where each nut and bolt goes on the top part of the engine .

Thanks for the help so far, guys. I managed to get my hands on the pre-formed heater hose going on the back of the block - now I just have to wait until tomorrow to install it. I'm not sure what the technical part names are for the two hoses - one comes off of the throttle body and heads toward the exhaust manifold (the hose has two 90º bends) and the other is also on the TB, except on the other side, going down the block on the exhaust side. They look to be 1/4" or 3/8" pressure-resistant hose, but the bends have me worried about replacing them with standard high-pressure hoses. The drain plug may be difficult to find... I do work at an auto parts store (I won't say which B) ) so I can get some of the harder-to-find parts.

Today I flushed out the system entirely using a store kit and I'll grab a HG leak detection system tomorrow - hopefully things are good, but I'm expecting the worst... I may be Supra-less in the next month :(

Well, I'm located in Fort Worth, and I'm cruising around, A/C on, and not going over half on temp gauge. I have a good aftermarket radiator of some kind that a previous owner put in, instead of the plastic end tanks it's all metal. If you have a pressure leak in your cooling system, you WILL overheat because the pressure in the system stops the coolant from boiling, once it boils and turns to a gas, it STOPS COOLING, once that happens, it cascades bad. I had that problem on my truck, had a pressure leak, nothing like overheating...IN THE WINTER.

I don't recommend stop-leak for anything usually, since it has a tendancy to clog things up, it's a band aid, better to fix it right the first time and not have problems with a clogged cooling system IMHO...

That sounds familiar... I've got the boiling coolant in the overflow - must have a pressure leak somewhere. Time to pressure-test the cooling system.

Bad radiator cap... :huh:

WOW!! If that was all, you are a very lucky person. But one thing for sure, you got a lot of good advice incase something like this happens in the future, and it sounds like you are going to do a lot of preventitive maintenance in the mean time. Fun stuff huh...... ;) .

Russ

Yep :lol: I kept trying to figure out why it was happening with none of the symptoms of a BHG...

Thanks for the great advice guys, I'm sure as to what to look for now when I suspect one going on.

i found this on another forum

i really like this and might keep a copy for quick replying

Default Re: car overheated
Head Gasket. Of course its your haed gasket, it is and always will be your head gasket. Replace everything exept your head gasket, see if that works, if not, spend 500+ Australian on a metal gasket, 200+ on some ARP Studs, put yourself in hospital using an in-bay lapping tool on your block and it will last till the end of time.
lol, sorry, i had to get that out of my system, im sure i will get hammered for it but it will be worth it.
Seriously, if your not loosing coolant, it could be a lot of things.