1986 Chevy cavalier (hatchback) with 2.0 Tbi motor.

So here's the situation, yesterday while sitting at a red light my temp light popped on and the car began to stall, got it into a parking lot and it died, tried to start it back up and it wouldcrank, but would not turn over. Had to get it towed home.
Today I charged up the battery and tryed to start it and it started right up. Left it idling in the drive way for about 15 minutes, turned the car off and the coolant was boiling all back into the overflow bottle. Decided to flush the old coolant out and replace it with new. After I did that I started it and let it idle, it idled for about 10 minutes before it shut its self off, coolant was boiling again! tryed to start it and it would crank but wouldn't start.
I've pretty much narrowed it down to a bad water pump. Because the heater core is bypassed and there is no thermostat in it. Now my question was, is there some sort of safety switch that kills the engine if it overheats?


~~1986 Chevy Cavalier CS~~
~~2.0 TBI~~

Also wondering if a faulty ignition control module (icm) would cause the car to stall if its overheating? I know the icm is very touchy when it comes to to much heat being applied to it


~~1986 Chevy Cavalier CS~~
~~2.0 TBI~~

Sound pretty bad if no T-Stat and overheating this badly....

I'd definately replace the water pump and the Radiator too. The radiators aren't too expensive these days and well worth saving the drive train ( an overheated engine can cook an Automatic Transmission ). I have an inexpensive mechanical water temp gauge hooked up to the head (at rear of engine) on my '86 Wagon too. That sensor is the one for the idiot light on my model anyways. All of these gives me great piece of mind as my Wagon is a daily.

I'd also recommend installing a T-Stat after you sort out the overheating. Engine temp has to come up for the sensors to let the computer know it has warmed up and come out of closed loop. It'll get better fuel mileage as well...

After you get the overheating in check maybe the stalling will go away as well.



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I had replaced the Radiator in the fall of last year, so i don't think it's that. I'm goingto pick up a new water pump tomorrow and toss it in. But with how quickly it had over heated (10 minutes idling in the drive way) it seems as though the fins might have separated from the shaft in the water pump and isn't moving the coolant. After it overheated and died out I felt around and every single hose was hot, so I don't think there's a clog in the system anywhere.
And it onlystalled yesterday (when I had to get it towed) but when I pulled over icould hearthe coolant boiling into the overflow tank.
And today when it was idling in the driveway it overheated, engine cut off and wouldn't start back up.

I'm hoping replacing the water pump will fix it


~~1986 Chevy Cavalier CS~~
~~2.0 TBI~~

Do the wp and new thermostat.I might suggest a new rad cap too.Why would you by pass the heater core anyway.Wp is cake on the cavs and it probably is shutting down due to temp.The only switches are the coolant temp,and dummy switch for low coolant on dash and the fan has a switch as well or sender.Idk right now kinda of tired and do not want to over think a simple item.

So I managed to get the water pump out today, and there doesn't seem to be anything wrong with it. The shaft spins freely, doesn't seem to be any wear on the fins, no leakage on the weep hole. Did figure out I've got a lifetime warranty so imma swap it out tomorrow.
But there has really got me stumped now. Hopefully changing out the water pump will fix the issue, if not, then I'm baffled.


~~1986 Chevy Cavalier CS~~
~~2.0 TBI~~

I would change the pump,replace the upper and lower hoses IF over 4years old and do a new thermostat and radiator cap.I would use some lime away to flush the system and hook back up your heater core into the cooling system.Do the work,put one bottle lime away in and heat on,fan hi and leave rad cap off for 15-20 minutes to flush the block out really good.The normal flush stuff will not cut thru years of crud like lime away.I would then drain and refill with just water and cycle for 15-20 minutes again.IF after the the first rinse still goo and or dirty water flush one more time to ensure the lime away is out of the system.Then add the normal green coolant and one gallon of distilled water(yes distilled) and mix to your ratio.I think having your heater core hoses not hooked up the water is not cycling thru and this flush should clean the block passages out better and I have done this so it is SAFE TO DO.Unless your coolant fan is not working,either sensor or relay or fan could be faulty.If the fan cycles on and off that is good,means good relay,sensor and it should kick on if engine goes above 205 I think on recall.I am betting you have trash in the block reducing flow and try this and then we can tackle the next step.

Check your oil to make sure you don't have a blown head gasket (the oil will appear milky), and make sure your rad fan is operable. Also look/smell to see if coolant is coming from the exhaust. Your head gasket may also be blown from the cylinder bore to a coolant passage and you'd be putting compression (and exhaust gas) into your cooling system. You will get compression (air pressure) in your overflow tank (bubbling) and your hoses will get larger and hard.
There are kits available to check if you are getting exhaust gasses in your cooling system:
http://www.ebay.com/itm/UV-560000-UView-Combustion-Leak-Detector-/330705124120?pt=Motors_Automotive_Tools&hash=item4cff8fbb18&vxp=mtr
There are only a few things that will cause your engine to overheat:
Bad water pump
Automatic transmission malfunction
Plugged radiator, block, heater core
Bad thermostat
Bad radiator fan/switch/sender
Blown head gasket
Cracked head/block
Low coolant level/ incorrect coolant mixture
If you overheat your car too many times (or one time too hot), you can crack the head or block.
Another thing to note: if you have low coolant, your temperature sensor will not register high heat reading because no hot fluid is flowing past them, so they won't know the engine is getting too hot.
And I'd never run a fuel injected engine without a thermostat. The engine needs to heat up in stages in order to let the ECM properly lean back the fuel as the car warms up. Too much fuel at operating temperature washes the cylinders out, hurts the rings, cylinder bores and pistons, and causes the car to eat way too much fuel.







~ Mike ~

So I've gotten the new water pump in, as well as replaced both coolant sensors and am still having the issue. I let it idle for about 10 minutes in the driveway and it begins to spudder and stalls out. Go to start it again and it only cranks but won't start. Did notice the exhaust manifold was glowing a little red before it stalled. Would a clog in the exhaust system cause it to stall after it warmed up? Maybe a clogged cat? There was exhaust coming out the muffler but it didn't seem like a steady stream, it sounded as though there was a misfire but I just put in all new plugs/wires and coil. So maybe a restricted cat is the issue?

Also, where is the fan relay located? I didn't notice my fan come on at all


~~1986 Chevy Cavalier CS~~
~~2.0 TBI~~

If your exhaust manifold is glowing that is not good.I would cut off the cat and run straight pipe temporarily unless you take it and get a new cat installed asap.This would kill the car running and might suggest going full new exhaust with new muffler bc the trash in the cat goes into the muffler.The cooling fan relay is on the LHS in front of the shock/strut tower behind the battery mounted on the fender if I am not mistaken.Your cooling system getting stupid hot may just be a a clogged cat and this will make the car cut off and or NOT run.No air flow is bad.Running out of go power and the exhaust being BLOCKED affect everything on how the car runs,drive,idles, and cools.

Updatessss

Got the cat off today. There was nothing left to it. It was literally hollow!!! So I did pick up a new one. Going to install it tomorrow. Now I'm thinking that my muffler is clogged, trying to brain storm how to remove all the catyalist from the inside of my muffler. Any ideas??


~~1986 Chevy Cavalier CS~~
~~2.0 TBI~~

andrew plosk wrote:Updatessss

Got the cat off today. There was nothing left to it. It was literally hollow!!! So I did pick up a new one. Going to install it tomorrow. Now I'm thinking that my muffler is clogged, trying to brain storm how to remove all the catyalist from the inside of my muffler. Any ideas??

Just get a new Muffler, last time I checked they were $25-40 for Jbody's for cheap ones at the auto parts stores.

i had a ecm go bad once that would never bring the cooling fan on but no codes. also i ran the car low once. temp light came on and within a few mins ses came on ran for maybe 1 min and died. i think gm built a fail safe in it for if it gets to hot it kills the car. another think to check is once the car gets hot feel the rad and see if its hot, if it is then you more then likely have coolant flow and need to see why the fan isnt coming on. another thing you can try is turn the a/c on and see if the fan comes on. when the ecm went i could do that and keep the car cool. also driving at hwy speed it didnt have a issue at all but once i came to a stop light 2 mins later it was over heating bad. limped to a parking lot and waited for it to cool down then went home. changed ecm and all was fine. the cars gone through 3 ecms in its lifetime. the other times were other things it was doing.

Just to throw my 2 cents in here. Sounds similar to this problem.....

Took the brown Cav out for test run today been sitting for almost 2 years and it started out great but by the time I got about 1 mile from my house I was losing power. Pulled over and engine was HOT, Oil filler cap was almost too hot to touch (radiator was really hot also), so I turned around limped home going about 5 MPH up the hill to my house all the while being passed by Acuras, Hondas and Mercedes (should have seen the looks I got). Spent about 2 hours checking things and trying to figure out the problem. Jacked up the back to replace the fuel filter and to my surprise there was insulation and cloth sticking out of the tail pipe, a mouse made a nest in the tail pipe. I guess that explains the hissing sound coming from under the car that I thought was a vacuum leak. So clogged exhaust = no power and HOT engine.

Well, more updates. Got the new cat installed this morning. Tightened all the clamps down and got it ready to start. Went to start it and now it just cranks and cranks but will not start. It is getting fuel, bought a new ignition rotor to drop in tomorrow and going to check for spark tomorow as well. But this has got me stumped again. After I chage out the ignition rotor imma gonna use a little starting fluid and see if I can't get it to start right up. If not then I'm thinking of removing the muffler and trying again, maybe the muffler is so clogged up that its completely plugged and not letting it start. If not then I'm completely lost!!!!!!


~~1986 Chevy Cavalier CS~~
~~2.0 TBI~~

Newest update, last update until I get my new muffler and put iton next week (my old one is still full of catalyst lol)

Yesterday I charged up my battery for a bit, pulled all the plugs and cleaned them off, checked all the gaps (they were fine). Replaced ignition rotor, cleaned out distributer cap. Tryed to start. Still would not start so I gave up for the day.

This morning it was pouring down rain and I've got no garage so I had to waitto work on it. Once the rain let up I wentoutto try and start it once again. Didn't get my hopes up, thinking it wouldn't start. Guess what??? It started right up!!!!!
The brown beater lives!! It runs perfectly fine now, other thena lil high idle.


~~1986 Chevy Cavalier CS~~
~~2.0 TBI~~

That is good hope it continues to improve.

It will improve over the next few days. Someone got me a setof super pricey nkg high end plugs for my birthday yesterday so imma drop them in tomorrow. As well as a new positive terminal setup for my battery. And someadvanced auto gift cards, so imma be doing big time tune up this week.

Also, could someone snap and post a picture ofexactly where and what the fan relay is located andwhat it looks like? I do believe I found it myself but I wanna make sure I'm replacing the right thing lol. The one I found is right in between the battery and the strut tower, bolted to the fender(I'd snap a pic but its past midnight and pouring outside right now)
And does anyone know how I could jump the fan motor to test it and make sure the motor itself works?

Ohhh and Ron, i sent you a PM, check it when you get a chance please, thank you


~~1986 Chevy Cavalier CS~~
~~2.0 TBI~~

Here Ya go Andrew -

Photo off my '86 Wagon ,it's right between the Battery and Washer Tank - can't miss it! I bypassed mine years ago and installed a mechanical temp gauge inside and switch for the fan - Now when in town or sitting in a parking lot I can cut the fan on as I need it.





Glad to hear you are up and running again!!



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Thanks Orlen!! That's exactly were I though it was. Just wanted to make sure lol. Now how did u go about bypassing it and running a switch?? I think I may do that. Just need to know exactly what wires the hot and ground and stuff


~~1986 Chevy Cavalier CS~~
~~2.0 TBI~~

Lawd, it had been so many years back when I did this I had to go and take a peek around today to remember what it was I had done! There is a Black wire, and a Black wire with Red Stripe going to the fan. I did this trick back in the day before I had any manuals of any kind for it.. I do know my fan is hot and what I did was picked up a ground under the dash (Steering column bracket) and went to the switch. Off the switch and to the Black wire going to fan. This way if I ever had a short all would happen was the fan would run.



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Thank you orlen. Thinking tomorrow I'm going to try and jump the fan motor to test it and make sure it actually works before I go through all the work of wiring it into a switch. I honistly can remember the last time I heard the fan turn on (which isn't good at all!!!!)

What I'm going to do it leave the fan hooked up to the relay and just splice into the wires, is the fan the only thing that's ran off of that relay?


~~1986 Chevy Cavalier CS~~
~~2.0 TBI~~

Yes, that is the only thing that relay does.




.

I checked the schematics in my factory manual for you. Black w/red stripe is positive at fan and come from relay. Black wire at fan is permanently grounded. You ought to be able to tap power directly from your battery and tap into the black/red wire and the fan should run even with no key in the ignition. These fans are routinely kaput due to their age. I have a couple spare known good ones from the yards because of this, and I often run mine with the switch to keep it used to being used, if you know what I mean.
Temp switch that operates the relay should be underneath the upper radiator hose and has a dark green with white stripe wire. You'll have to remove the air intake out of the way and heat stove hosing to get good access. Ground this wire with ignition on and the relay should click and fan should come on. Bad fan - relay should at least be clicking as it is energized and reset.
The factory shop manuals are on EBay and very reasonable prices and are great to have!!




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Awesome, thank you so much!!!! Gonna tackle the fan tomorrow. After I go rent a cut off wheel so I can chop off my old muffler (full of catalyst) and toss my new one on.
if I test the fan motor itself and its not working, I don't have to get a new assembly right? I should just be able to purchase the motor itself? I'll check around and the junk yard before I make any decisions though. Did happen to find an exact replacement at autozone for only $23.99 such isn't to bad.


~~1986 Chevy Cavalier CS~~
~~2.0 TBI~~