Car likes to overheat

[PerfectCreature]

I have a situation where the car runs a little high for the "normal" temperature. It likes to sit at about 205. It stays there, sometimes goes down to 200, and then rises to 205 while I am driving highways speeds, but once I get to town the temperature rises. I had it rise to about 230-235 the other day while I was driving around town running errands.

I took a look at my radiator as I assume that is the first thing I should check, and it looks pretty clogged with smaller rocks.
I also am pretty sure my fans are not coming on either.
I turned on my AC and the fans in front of the radiator should run right? Well, they don't if they are supposed too. I hear the compressor turn on. I did the same thing for the heat as well, and the front fans did not turn on (not sure if they are supposed to or not).
It is getting annoying not being able to idle and have my car keep itself cool.

Looking for any other suggestions.
I could try to take a photo of my radiator if that would help?

[TGP37]

Some ideas.....

T-Stat going bad or is starting to clog
pressure loss in coolant from rad cap failure
Coolant system needs a flush
Coolant is getting low in the radiator, fill directly into radiator not over fill tank
Rad fans failing (bad relay, blown fuse, failing PCM, unplugged, bad ground)
faulty radiator clogged up internally

or the cooling system is fine and the car is running hotter from....

fuel pump starting to fail
fuel filter clogged up (had this happen to me once)
head gasket failure
or other issues that cause heat increase


220 isn't all that bad and many cars run at their best around those temps. 235 is a bit high though and the fans should definately come on at that temp.

[PerfectCreature]

Some ideas.....

T-Stat going bad or is starting to clog
pressure loss in coolant from rad cap failure
Coolant system needs a flush
Coolant is getting low in the radiator, fill directly into radiator not over fill tank
Rad fans failing (bad relay, blown fuse, failing PCM, unplugged, bad ground)
faulty radiator clogged up internally

or the cooling system is fine and the car is running hotter from....

fuel pump starting to fail
fuel filter clogged up (had this happen to me once)
head gasket failure
or other issues that cause heat increase


220 isn't all that bad and many cars run at their best around those temps. 235 is a bit high though and the fans should definately come on at that temp.

The T-Stat is brand new, maybe a few months old. I had it pressure checked and everything was solid. The coolant was flushed as well as the fuel filter was replaced.
The fuel pump, radiator and fans (relay, fuse, bad ground etc)
I hear the fuel pump turn on as soon as I start the car, should I be looking for something more specific? I remember someone mentioning what to look for but I forgot what it was exactly.
Where are the fuses for the radiator fans? Where would I look for them to have a bad ground or be disconnected?
I will try to post a photo or video or something of my radiator.
I also had a bad LIM gasket, which led to a bad headgasket which I drove with for 5-10k miles before I had it fixed, so the radiator could be clogged internally I guess. Although the fluid is still orange.

[TGP37]

So you have pressure in the coolant system, that is a good sign for that system.

Is you ECT sensor working? Car only knows when to turn on the fans from data from that sensor. But I think the fans are on 100% if the ECT sensor fails, but that is just an assumption.

Everything is fused or has a fusible link in the wire.

Bad fuel pumps sound gritty, chaotic, weak, fluttery...anything but smooth tone when pressurizing. Remove pressure from the fuel rail (schrader valve or sit over night) and prime the fuel pump, you'll hear it pressurize well if it's good.

The fuel filter, those are commonly over looked or not replaced when they should be. A clogged filter will reduce pressure and flow rate making the engine run lean if the problem goes beyond the PCM's ability to correct the lean condition. When my fuel filter went bad I was able to floor it in park and bounce of the rev limiter twice then it started to bog down from lack of fuel pressure.

Does your exhaust smell funny, stinks in a non-normal smell?

If your radiator is that bad, why not replace it?

Belt not slipping is it?

[ericjon262]

I would start with the fan relay, cheap and easy to fix if that's what's wrong.

[PerfectCreature]

So you have pressure in the coolant system, that is a good sign for that system.

Is you ECT sensor working? Car only knows when to turn on the fans from data from that sensor. But I think the fans are on 100% if the ECT sensor fails, but that is just an assumption.

Everything is fused or has a fusible link in the wire.

Bad fuel pumps sound gritty, chaotic, weak, fluttery...anything but smooth tone when pressurizing. Remove pressure from the fuel rail (schrader valve or sit over night) and prime the fuel pump, you'll hear it pressurize well if it's good.

The fuel filter, those are commonly over looked or not replaced when they should be. A clogged filter will reduce pressure and flow rate making the engine run lean if the problem goes beyond the PCM's ability to correct the lean condition. When my fuel filter went bad I was able to floor it in park and bounce of the rev limiter twice then it started to bog down from lack of fuel pressure.

Does your exhaust smell funny, stinks in a non-normal smell?

If your radiator is that bad, why not replace it?

Belt not slipping is it?

My belt does not slip, it was replaced about 10,000 miles ago? Maybe not that long. It shows no signs of wear, nice and snug.
My exhaust smells as it should, I suppose. Nice and hot, no water residue.
I am pretty sure my pump takes only a few seconds to pressurize. I will listen to that tomorrow morning.
I replace my fuel filter once per year, everytime I register my car So that is brand new- 3000 miles on it, tops.
So, I guess it leads me to belive perhaps the radiator should be replaced.
I will poke around my fans.
I am correct that AC should make those two front fans turn on, right?
Where am I looking for for the fuse wires though?
What should I be looking for for it to be faulty? Or am I just going to buy/replace whatever fuse/relay is there?

Also for radiator:
Does anyone know which one I am looking for? (Obviously the AC Delco one, but didn't know if any of the others were just as good)
2003 Grand Am SE1, Auto 3.4

Did a search on Amazon and found these ones:
http://www.amazon.com/gp/part-finder...&vehicleType=5

[TGP37]

Here are diagrams to help. They are for my 96GPse but they should be similar if not identical to yours.

At this point it seems like the fans are not turning on when they should. I think this is the root of the over heating issue.

You can try jumping the relay pins marked in red, carefully not to shock yourself. If that doesn't turn the fans on, check the extra large maxi fuses, #3 specifically on my car. Or check and see if you get any resistence between the fan pin and the engine ground (frame/bolt/batt neg). the motor will have some resistence to ground, if you get any it is most likely not a broken circuit there.

If they do turn on, then the PCM isn't triggering them to turn on.

The PCM grounds the connection and if that fuse which powers the relay was blown, your car wouldn't run, it powers the PCM as well.

[PerfectCreature]

Alright, I will try that as well.
I am also looking at getting a new radiator, since I have had several gasket issues in the past, my guess is that the radiator is clogged and not working very efficient.
The combination of the fans not turning on as they should could make perfect sense.

[PerfectCreature]

I went poking around my engine bay today, and I found something odd.
I remember my mechanic saying something about a heater core hose that had broken when I blew my head gasket.
I thought he had replaced it, but I guess he used a makeshift hose.
Could this makeshift hose have anything to do with my overheating at idle?


It is bent where the arrow at the top is pointed. I am assuming that is the heater core hose, though I am not sure......

[pocket-rocket]

If that's the line coming off of the thermostat housing, it could be knocking the flow pattern off coolant out of whack causing the gauge to read off. That doors look like your heater core line, I bet you have little to no heat right now, too.

Sent from my HTC One X using Tapatalk 2

[TGP37]

I suppose it is possible to effect coolant flow but I wouldn't count on it. Fix it and hope for the best.

Not sure how proficient you are with motors so I gotta ask.....when you check your coolant level, do you check the rad fill cap or the over flow tank?

Also, there are two points on my 96GP that needs bleeding if the coolant got too low. One is just above the water pump, a bolt on top of the tower looking water feed line, the other on the tstat housing.

When I fill up the coolant in the rad, I open up the bleed lines so the trapped air doesn't prevent a full fill up. Close bleed lines then I start the car with the rad cap off and gently bump the throttle to burp the rad. Fill to neck if the level drops. You got about 30-60 seconds before engine heat causes the coolant to flow out.

If the overheating is just at idle, consider the t-stat failing. Or the water pump isn't working very well anymore but I would suspect coolant puddles near the pump typically.

A way I would test the water pump is get your car running hot, then shut if off. 10 minutes later the coolant should be even hotter from sitting, heat soaking. Start the car and note the coolant temp, it should drop down within a minute if the pump is good.

Does your coolant temp spike close to red line then fall back to operating temps when warming up?


Running too lean at idle can cause overheating. And running lean can happen from leaks in the intake system pas the MAF sensor (if you have one). Could also happen from clogged fuel filters, bent/kinked fuel lines or even bad battery terminals.

[pocket-rocket]

If he is using the gauge for temps and not scanning the pcm I bet the overheating is just on the gauge because of the coolant flow when in reality the actual engine to is in acceptable limits.

Think heat soak at the CTS area.

I mention it because when Ben bought a 91 Cutty 5 speed dohc from Nico, Nico had bypassed the tb coolant line in a way that caused coolant temp to not be read correctly, so I know disturbing the coolant flow can mess with things.

Sent from my HTC One X using Tapatalk 2

[TGP37]

If he is using the gauge for temps and not scanning the pcm I bet the overheating is just on the gauge because of the coolant flow when in reality the actual engine to is in acceptable limits.

Think heat soak at the CTS area.

I mention it because when Ben bought a 91 Cutty 5 speed dohc from Nico, Nico had bypassed the tb coolant line in a way that caused coolant temp to not be read correctly, so I know disturbing the coolant flow can mess with things.

Sent from my HTC One X using Tapatalk 2

Interesting, I didn't doubt it...just seemed unlikely. But hey, if real world experience says it does.....can't argue that.

I do know the in-cab coolant gauge isn't marked accurately as a result of too many consumers complaining of over heating when in reality it was just normal flux.

I would still think the fans would turn on though, eventually.

On that note of normal over heat PerfectCreature, a lot of cars run at their best efficiency around 210-220F.

[pocket-rocket]

I would still think the fans would turn on though, eventually.

Yeah, this also makes me think my opinion could possibly be true, but still, do make sure the fans are functional for sure.

I'm trying to think what all could set the PCM into fault mode and kick the fans on. What about disconnecting CTS and IAT to do it?

I would still like to find out what he is using to collect his engine data. Although if it's a 3 wire CTS, the gauge should read pretty much identical (minus the built in flaw from customer complaints) to what the PCM is seeing which would make me think it would command the fans on.....

Either way, taking that kink out of that heater core hose would be nice with cold weather just around the corner.

[PerfectCreature]

If that's the line coming off of the thermostat housing, it could be knocking the flow pattern off coolant out of whack causing the gauge to read off. That doors look like your heater core line, I bet you have little to no heat right now, too.

Sent from my HTC One X using Tapatalk 2

No, I have full heat which is odd based on how bent the hose is. It gets blistering hot-blow dryer hot at full temp. I have ordered a new one for the spot. I am hoping that may curb the overheating issue. I am having the mechanic check the radiator too, I tried checking the fans, but they didn't turn on. So he is going to look at those too.