01 cavalier overheating

I searched and found a few threads that pertained to my problem, but did not really help.
My wife has a 01 Cavalier with the smaller of the two motors (2.2 I think)
with auto trans and A/C

My son drove her car and it overheated. We took the car to a shop because there was pressure blowing back into the radiator. They said the machine shop told them the head needed to be shaved. They installed the shaved head, installed new thermostat, and belt. We drove the car on day 1 and the temp was 195 to 210. next day it overheated. I removed the thermostat and it ran cool. We carried it back on Monday to the shop and they said it must had been the thermostat was bad. They replaced it. Same thing. Ran fine day 1, next day, overheating.

When it ran hot the radiator was cool. I waited until the block cooled, removed both radiator hoses, ran a garden hose through the top hose and water poured out the bottom one real good. Put garden hose in bottom one and water poured out the top one fine. I replaced the water pump. Still runs hot. Even tried running watter through block (When it was cold) and there is no obstructions. Now I did notice that the "Engine" and "Trac" lights are on all the time. Also the 30 amp fuse was blown for the fan. replaced the fuse and it blew too. I noticed in another post the poster was told to "Jump" the relay. How is this done? I also read another post where someone was told to turn on the A/C and the fan should come on. Mine does not (Guess its the blown fuse). After removing the thermostat for the second time the car runs cool and the radiator is hot all over (Top to bottom, left to right). Also I assume the thermostat was installed correctly by the shop, the pellet was towards the block. I do notice thet if I squeeze the upper hose while the car is running I really can not feel the water trying to pass through, almost as if the pump is not pumping. I assume this is because of some by-pass line or something. I checked the belt diagram on the hood, the pump supposed to turn anti-clockwise and it is.

Any thoughts? Please try to explain in simple terms as a mechanic I am not, I am a carpenter and plumber, have not worked on cars since about the 70's!

Thanks.

maybe I posted this in the wrong place?

no your in the right place you did do a good job of explainning too.when you say the car over heated what do you mean by that, hit red line or just got hotter than you thought .The fan defenitly has a short in it as you keep blowing the 30 amp fuse. From what I know three three things control the fan .1 the motor ..check by unpluging and run 12 volts off battery or back prob with 12 volts from battery. 2 relay switch can be checked with 12 volts too look at relay and make it click by crosssing terminals or have parts place check for you. #3 engine coolant temp sensor or ETC which sends signal to ECM. ECM signals relay, relay to fan motor. Side note: ETC also helps or signal is used by other emmisson control componets .# 4 ground you must have ground to complete circuit in cars,check ground. also power continuity no shorts grounding out which could be your case. also fan motor frozen causing short blowing fuse.
next your t-stat, rad, water pump but it sounds as though you have covered those problems. address the blown fuse and I think you will be good to go,let us know

Air In the system???. Also a good quaility thermy . Get an OEM one. Get it pressure tested just for kicks ,see if it loses pressure indicating a leak inside or out . I`m bettin air tho

Running hot = very close to 260. Did not let it get there, but it got close
Fan = The old fan was worn out, removed, used two seperate wires, connected to battery, sparked, wire got hot, fan not turn, replaced fan
No air in system, that was one of my earlier thoughts. I am not a machanic, but I am a licensed plumber and I know what air will do especially with a jet pump.

Will check out the relay. I assume the relay works as any other relay, connect 12 volt to the switch side and it should click. If not, bad relay?
Can i or should I check across the load side as I apply battery to the switch side?
Would any of this keep the trac light and check engine lights on all the time?
Sound right?

so far so good , But as you say something else is up you can get a code scan at local parts store: auto zone or advance for free. See what codes you come up with and see what store recommends per code. A code means that some emmission control system on your car is not working right and while your at the auto parts joint get a Haynes Repair Manual very helpful.
just guessing but code may have something to do with the car not reaching temp no t-stat ????? try to cover all the bases when you get code . read chapter 0 troubleshooting, 1 cooling check, chapter 3 and 6 about emmissons
sorry about the switch question not sure I have to have mine checked I am down the street from parts store.But you can see diagram for switch on the side and give it a shot because I always do and have not screwed up much yet.

UPDATE
The relay for my car radiator fan is a normal open circuit.
It tells me that the contacts # 85 and 86 activate the relay.
Then the contacts # 87 and 30 send power to the fan
I jumped between contacts 85 and 86, then between 87 and 30 and the fan comes on! Now I remove the jumpers and use the cars battery to jump from the contact # 85 and 86 and the relay clicks on! So, why would it work when I jump the relay, but when I plug it into the socket it wont work? I am thinking maybe the contacts below the relay in the box. I tried to bend them slightly to assure contact but maybe I did not bend them enough?

Thanks for any input as I seem to be soo close to figuring this thing out. Thanks.

OK.....here is what I know about these GM/Delco relays.

85 ... is the ground on the coil side of the relay.
86 ... this goes to + 12vdc or other side of the relay. this is what actually activates the relay. This would be a signal from the ECM.
87.. I call this the load terminal. This goes the fan. +12vdc
30 ... I also a +12VDC ..coming from the fuse.

So....when the ECU get a signal from the Temp Sensor that the engine is hot or reached a certain temp. It then sends a +12vDC signal to the relay #86 to activate the coil....creating a magnetic field attracting the armature. The armature holds the contacts. So now ( normally open) the contacts mate closed (30 & 87) applying +12VDC from the HOT fuse line to the load or fan.
One side of the fan wire must be grounded to the engine/frame.

So just to check the fan and the wiring to it....Pull the relay, make a jumper wire, and connect #30 to #87. But first make sure you have +12vdc on #30 coming from the fuse. Use a test light or DVM.

What I have done is...I have a "test relay" ..I have removed the cover and I manually activate the armature, closing the contacts. Quick and simple !

That's my stories and I am sticking to it !! Cheers Mate :)

JzJzz and the Man from Down Under !!!!

OK.....here is what I know about these GM/Delco relays.

85 ... is the ground on the coil side of the relay.
86 ... this goes to + 12vdc or other side of the relay. this is what actually activates the relay. This would be a signal from the ECM.
87.. I call this the load terminal. This goes the fan. +12vdc
30 ... I also a +12VDC ..coming from the fuse.

So....when the ECU get a signal from the Temp Sensor that the engine is hot or reached a certain temp. It then sends a +12vDC signal to the relay #86 to activate the coil....creating a magnetic field attracting the armature. The armature holds the contacts. So now ( normally open) the contacts mate closed (30 & 87) applying +12VDC from the HOT fuse line to the load or fan.
One side of the fan wire must be grounded to the engine/frame.

So just to check the fan and the wiring to it....Pull the relay, make a jumper wire, and connect #30 to #87. But first make sure you have +12vdc on #30 coming from the fuse. Use a test light or DVM.

What I have done is...I have a "test relay" ..I have removed the cover and I manually activate the armature, closing the contacts. Quick and simple !

That's my stories and I am sticking to it !! Cheers Mate :)

JzJzz and the Man from Down Under !!!!

OK, It seems to be maybe this ECU thing. Exactl what is it and where can it be found?

Ok....at this point....do as previously noted, go buy a Haynes Repair manual for this car. ECU...Engine Control Module is also called a PCM....PowerTrain Module or the brains of the car. Location is noted in this book.

Wiring diagrams are in the back of it....$$$ well spent.

I stand corrected to my previous post...

So....when the ECU get a signal from the Temp Sensor that the engine is hot or reached a certain temp. It then sends a "ground' signal to the relay #86 to activate the coil....creating a magnetic field attracting the armature. The armature holds the contacts.

JzJzz ....and the man from Down Under....Cheers Mate

just a quick suggestion. Check the harness with a big ole' connector that runs under the battery tray. I had problems with one of the relays up front, the DRL, and it was because the wires had rotted out of that connector. terrible place for it BTW.

I'm new here and probably posting in the wrong place but I'm not really good at these 'posting' sites... please work with me.

I was reading the 01 cavalier overheating. I just bought mine in 07 and this weekend I too had a similar problem but have a question.

I drove a distance which I usually don't as I live in the core. My temp guage seemed fine never reaching the red. It tipped that way a few times but never anything to worry about (If I trust the guage)

However, after I returned to the city, I went approx 3 km and when I started the car, my engine, battery and oil light were coming on and the car kept stalling (the heat guage was normal) I limped home (about 3 km.)

When I opened the hood, you could not touch 'anything' under there. This included the oil check thingy. There was no pressure in the rad hose which is leading me to believe my thermostat is acting up. (replacing that today as it's the cheapest start point)

My question is this...Normally she fires immediately when I start it. On that particular day, I missed it and had to restart it (having the turn over a few times). Could this trigger something with the sensors if it has to hesitate to start? I know it sounds lady minded but I have to ask as she usually runs great... ?

Is it loosing water or antifreeze ???
Is the CEL on ?? (Check Engine Light)
Yes, replace the theromstat and make sure all the air is out of the system.

I dont know of any sensors that would fry, if the engine overheat for a long time. Worse case is a blown head gasket or warpped head.

Coolant Temp. Sensor....have it checked. But If bad, i would think you would get a CEL.

You can get the system pressure checked at a Radiator Shop. They also can check to see if there are any exhaust gases in the water.

If the CEL is on......get the codes read.

Jzjzz......and the Man from Down Under...Cheers Mate.

Thankyou for your reply Helmuth48

I've changed the thermostat and there's some leaking going on but I'll sort that.

This is really going to sound terrible, but the trip I had made out of town was approx 30 km there and back. After reading the posts above, I found....

I had no fan.

As posted, I turned my AC on, and lo and behold, there was a fan.

I am now assuming it's a relay as my fuses are fine and the fan is still not working.

As for your question, no, I wasn't leaking any fluid and the temp guage was still in the center. This is what really baffled me. The car (which is a die-hard) still ran for me until it was finally too hot and would stall.

I'm now either going to change the relay ' or ' wire direct. Anything I need to know before the do the latter as a relay here in Ontario Canada at my local garage is not found except from the manufacturer.

Thanx for all your help

My advise to you now also, buy a Haynes Repair Manual. About $20 buck US.....it will pay for itself. Ebay or elsewhere on line, several options.

So, you did not say that the CEL was on ???...So I assume it is NOT. So what is it ON or OFF ??? this is an important answer!!! :(

If the fan comes on with the A/C on...it is not the Relay...I believe it uses the same relay ( if you had the book, you could tell from the wiring diagam).

Engine coolant Temp Sensor (ECT)....check it out...may not be sending the needed signal to the ECU. Remember it is not the same, as the Temp Indicator Sensor. Also as Kirkwood158 noted that sensor ECT, also sends data to the Emission system...



Cheers Mate...good luck.... JzJzz.......

The only light that's on is my rad light. It could be because we changed the thermostat and possibly there may still be air in there. It's antifreeze that I'm leaking but we tightened everything up. We'll sort the air thing out tomorrow.

The garage I deal with talked to me on the phone (I explained the situation) and he felt it was a relay but wanted me to bring it in. He said that he had to order one for a 2001 before but I will print your post and take it to him before ordering anything.

I've been running my AC to ensure that I have 'a' fan. I don't trust the regular one now and I'm not sure how long it's been this way. As I said earlier, I only stay local and still wouldn't know if this hadn't happened. There are no signs as the temp guage stays kosher. I will keep you posted in case someone else has the same issues.

Thanx again

According to my wiring diagram....if the fan comes on when you turn on the A/C....it is not the relay.....I sitll say....check the ECT sensor...

That is my story and I am sticking to it !!!!

Cheers Mate...JzJzz