87 GL Wagon running hot. Suggestions?

[brigham biker]

I recently acquired an '87 GL Wagon, 1.8l, FWD, 3spd auto. It needed timing belts which were included with the car. I had a local mechanic install them. The car starts right up, idles nice & smooth, gets about 25+ mpg & goes down the road straight. I cleaned it up put some new tires on it and gave it to my daughter to drive to school. Problem is it seems to be running hot. It has gauges. Temperature runs in the high "normal" area to just over the line into "hot" or red area. It also belches coolant out of the top of overflow reservior when at its hottest, usually soon after a radiator top off after an "overheat" incident. I have been topping off radiator but only add coolant to reservior if level is at or near bottom line on tank. After checking out alot of postings here I am hoping to get some suggestions for problems to look for and solutions to try.

[Subruise]

sounds like a headgasket. check the thermostat tho and make sure thats not it. with these things when they overheat/blow HGs they can warp the heads pretty bad.

 

but on the bright side, i had an older one that ran with a bad HG for & years....just keep putting water in it:lol:

 

 

RV

[GeneralDisorder]

Possibilities:

 

1. Radiator cap failure.

 

2. Cooling system leak. Pressure test it. There are a few small coolant lines under/around the intake that can spring pinholes, radiator leaking at a seam, heater core hoses, heater core itself, etc. Check everything.

 

3. Clogged radiator - check for good flow - a laser temp gun is useful to check for cold spots on the radiator. Large cold areas while the engine is up to temp and still climbing indicate area's where flow is restricted or cut off.

 

4. Intake manifold gaskets (yes coolant flows through them)

 

5. Head gaskets. Only go this far once you rule out 1 through 4. Usually manifests itself as combustion gasses over-pressureing the cooling system and causeing the radiator cap to burp out the gas and a bunch of coolant along with it. They eventually run low on coolant and overheat. There are ways to check for combustion gasses dissolved in the coolant. A shop could test for this or there are chemical strips that you can buy as well.

 

It is also possible that you just aren't getting all the air out of the system. Air bubbles will prevent circulation in the system and are a common cause of overheating after recent mechanical work has been performed. Make sure the car is pointing uphill and run it with the cap off while filling it and massaging the hoses to get the bubbles out.

 

GD

[Ricearu]

+1 Head Gaskets

 

Neverending bubbles in the radiator with the cap off are a good "laymans" sign of Head gaskets being blown. but not ALWAYS detectable.

[brat82]

howdy,

This sounds like the thermo is sticking. I'd check some of the easy things first. I've had thermos fail right outta the box. Can check these outta the engine, w/boiling water and cooking thermometer. Does your electric fan come on? If it doesn't it, could be its sending unit, in the radiator. I've had clogged radiators, that couldn't be cleaned out. The radiator guy told me that "off the shelf" radiator products usually result in radiator clogs. If you have a leak in the gaskets, you might see something other than air bubbles in the radiator fill, or maybe even in the oil. Some repair shops may be able to put analyzer on radiator fill and see if there are exhaust gases there(leaky headgaskets,etc)

[idosubaru]

there's a hundred possibilities - read GD's list.

 

i would focus on trying to determine the following which will help us help:

 

are you loosing any coolant when it's NOT overheating. in other words if you drive it around and check levels before and after, without running it hot, is it loosing coolant?

 

any signs of leaks anywhere?

 

the "bubbling" isn't necessarily a "headgasket" symptom, it is sometimes but not all the time.

 

that being said, fix this NOW or you're going to be stuck with scrap metal. running a 20+ year old car that hot is not good for 20 year old head gaskets and seals, you're likely to blow something. if you had to pay for timing belt install you'll definitely be paying for a head gasket job which for newer cars is around $1,000.

[brigham biker]

thanks for all the great info. it gives me places to start looking. i really hope it isnt head gaskets. could i check for head gasket leaks by doing a compression test?

 

i have replaced the thermostat with a new one which i tested before installing it. there are no outward signs of coolant leakage that i can find. only coolant seen is when it comes out of top of overflow reservior when heated up.

 

more info about how and when it heats up: driving it around town, lower speeds, short distances, the temp stays midrange in the normal zone of gauge. driving it on freeway, higher speeds, longer distances is when the temp starts to climb into the top of normal zone. could it be something as simple as a loose fan belt?

 

the electric fan seems to be working. that is to say it comes on but only when nearing the very top of normal zone. shouldn't it come on sooner? could that thermoswitch be working but flakey? can that switch be bypassed and wire the electric fan to come on whenever the car is on? or is that a bad idea? this could help me figure out if the thermoswitch is flakey or not.

 

what about the mechanical fan clutch? i suspect it may be bad because when engine is off i can manually turn the mechanical fan and it turns easily not free wheeling but easily whether engine is hot or cold. shouldnt that clutch be loose when engine cold and tight when engine hot?

 

i am going to use some of the suggestions and get to work. thanks for all the great input.

Edited August 11, 2010 by brigham biker
left out info about replacing thermostat and no signs of coolant leaking

[john in KY]

Just replace that 23-year -old radiator.

[unibrook]

You can bypass the thermoswitch by turning on your AC + fan on you internal cabin controls. The AC tells both radiator fans to turn on, thus providing extra cooling. But you need to turn your dash fan on also. shouldn't matter if you turn it to Fan 1--4. Any of those settings should work. Just lift the hood, turn those switches on and see if both fans turn on. You will need to check your coolant level daily from now on. The joys of old car ownership.

 

TLC sponges!

 

[Virrdog]

My car is exhibiting very similar symptoms. Only difference is my car likes to run cold... until it gets up to normal on the gauge, which means its on its way up and the heater comes on.

 

Any progress in diagnosing it?

[mudER wagon]

sounds like a headgasket. check the thermostat tho and make sure thats not it. with these things when they overheat/blow HGs they can warp the heads pretty bad.

 

but on the bright side, i had an older one that ran with a bad HG for & years....just keep putting water in it:lol:

 

 

RV

 

:eek: SAY WHAT?!

[Nug]

Just replace that 23-year -old radiator.

 

This couldn't possibly hurt. It's probably full of junk.

[edrach]

I'm with John in KY, a car that doesn't overheat when driving it a lower speeds and on a level stretch and then heats up (i.e. the faster you go the hotter it runs) has always been a radiator when I've had that symptom. However, follow GD's advice to confirm the radiator might be the problem. A new radiator runs about $100; no need to get an over-sized one. Don't waste your money on a radiator flush; put it toward the radiator.

 

I see you already replaced the thermostat; I hope it was OEM. After market 'stats seem to be a problem for some reason.

[Virrdog]

a car that doesn't overheat when driving it a lower speeds and on a level stretch and then heats up (i.e. the faster you go the hotter it runs) has always been a radiator when I've had that symptom.

 

Hmm, gotta listen to the voice of reason... But in my case I replaced the radiator 2 years ago.