No Heat and High Temps

[Draconic]

I have 99 Grand Prix and I have had this issue reoccur several times now. The first time I took it to AAMCO and had them replace the water pump, that fixed it for a while. Then the problem popped up again a few months later. So I took it back to AAMCO and they replaced the popular problem of the elbow with the allum one. That lasted about a yea and then the issue came back. I'm losing coolant and I have no heat. The temp skyrockets after about 5-10 minutes of driving to the 210 mark and stays there and will go above it now (to last mark before overheat) and then after a stop and rapid accelerations will plummet to 210 sometimes and other times not.

I'm going to attempt to open the bleeder screw by the therm housing when I get home because I'm at work and don't have any tools on me (i.e the 7mm wrench I need) but I can't imagine that air in the cooling system alone would cause all this?

Any suggestions?

[FordMan77]

If you are loosing coolant and don't see ANY visible leaks then your lower intake gaskets are shot or the UIM is cracked and you are burning coolant/getting coolant in the oil. When you pull the dipstick does the oil look clear, or kinda muddy/milkshake color?

The no heat thing is likely some trapped air somewhere in the system. These cars are known to do that if not bled properly. Also, how low on coolant are you really? This will cause a no/low heat issue as well. If it is the LIM gaskets leaking then you need to quit driving it now before you spin a bearing and trash the motor. Get that done asap.

[Draconic]

If you are loosing coolant and don't see ANY visible leaks then your lower intake gaskets are shot or the UIM is cracked and you are burning coolant/getting coolant in the oil. When you pull the dipstick does the oil look clear, or kinda muddy/milkshake color?

The no heat thing is likely some trapped air somewhere in the system. These cars are known to do that if not bled properly. Also, how low on coolant are you really? This will cause a no/low heat issue as well. If it is the LIM gaskets leaking then you need to quit driving it now before you spin a bearing and trash the motor. Get that done asap.

Thanks for the response.

Well I ran it and opened up the bleeder screw and got nothing but steam and no bubbling so I'm assuming that means no air in the lines. There is a milkshake like goop on the bottom of the Oil cap but that could be from condensation because I only drive this car 17 miles then it sits for about 10-11 hours only to be driven another 17 miles and it is winter time otherwise I may be looking at a blown head gasket. I need to be able to drive it for a day and half before I take it to Pep Boys to get it looked at but since the LIM gaskets going seems to be a common issue with the Grand Prix's 3800 series engine I'm thinking it might just take replacing the gasket. When i get there I'll make sure they do a pressure test but hopefully it's not both the LIM Gaskets and the UIM being cracked.

Any ideas on a short term temp fix to hold me over?

[Scottydoggs]

you leave the bleeder open till coolant comes out, if steam came out theres still air inside the engine.

[Draconic]

you leave the bleeder open till coolant comes out, if steam came out theres still air inside the engine.

Do you know about how long it could take? And what if coolant never comes out? I would think that means there is an issue some where between the reservoir and the radiator but I will attempt to bleed it for a while in hopes that eventually fluid will come out.

Thanks guys. This is an immense help.

[Scottydoggs]

if coolant never comes out id look at the at the water pump.

drive the car till its warmed up, then leave it running and crack the bleeder, leave it open till coolant streams out solid, no bubbles or steam. just coolant, then shut the screw.

[Scottydoggs]

if it bleeding it stops it from overheating or getting hot and you still have no heat in the car, you can try flushing the heater core. take both heater hoses off the alt bracket, put a garden hose to one hose and flush it till clear water comes out the other hose. then switch hoses and back flush it.

[Draconic]

if coolant never comes out id look at the at the water pump.

drive the car till its warmed up, then leave it running and crack the bleeder, leave it open till coolant streams out solid, no bubbles or steam. just coolant, then shut the screw.

The water pump was replaced about a year ago and the elbow not long after that. I would hope it's not the pump, not to mention a leak there would be noticable just beneath it if i'm not mistaken. But I will definitely let it bleed until fluid comes out. Hopefully I'll see some come out.

[BillBoost37]

Pull thermostat housing. Pull stat and if the level is low in the LIM, fill through that hole. Sometimes they can be difficult to burp.

[Draconic]

Pull thermostat housing. Pull stat and if the level is low in the LIM, fill through that hole. Sometimes they can be difficult to burp.

Not sure what you mean by "Pull stat and if the level is low in the LIM, fill through the hole"

[BillBoost37]

Follow the top radiator hose to the engine. The piece it is attached to has two 10mm bolts. If you remove those, the thermostat housing and top hose will lift up. Directly below that metal housing is the thermostat. Once you remove the thermostat, if the coolant level isn't right at the top of that manifold that you took the stat out of.....(it should be) fill it through that hole and reassemble the parts you took apart. Now fill back up at the radiator and see if that fixes the issue.

[Draconic]

Gonna replace the stat and burp the system to see if that fixes it. I'll keep you updated. Thanks everyone!!

[Draconic]

Follow the top radiator hose to the engine. The piece it is attached to has two 10mm bolts. If you remove those, the thermostat housing and top hose will lift up. Directly below that metal housing is the thermostat. Once you remove the thermostat, if the coolant level isn't right at the top of that manifold that you took the stat out of.....(it should be) fill it through that hole and reassemble the parts you took apart. Now fill back up at the radiator and see if that fixes the issue.

Latest update. I replaced the state and when I did I found out why I couldn't see a leak on the outside. The block was bone dry of coolant. I filled that put the state and housing back on and filled by the cap until it was full. It ran at temp and gave heat. Thats when I looked under while it was running and saw the leak. As it ran the leak got worse. Then it stop when I turned it off.

Thoughts?

[Scottydoggs]

wheres the leak?

you got coolant elbows, water pump leaks and worst case is a rusted out freeze out plug, or it got cold and your coolant was not up to snuff and it popped the freeze plug out.. you'll need to fill it and follow the wet trail.

[Draconic]

wheres the leak?

you got coolant elbows, water pump leaks and worst case is a rusted out freeze out plug, or it got cold and your coolant was not up to snuff and it popped the freeze plug out.. you'll need to fill it and follow the wet trail.

Hard to tell. It's back center from the looks underneath. it all but stops when the car is off. Just drove to work And had it staying below 200 (the first mark above 160) for most of the trip with heat but not as hot as I know it can get. Heat lasted about 15 miles than stopped being hot and the temp started going up again. So where ever the leak is it's keeping it from getting to the heater core and back to the radiator to cool off.

Here's the video of it leaking https://www.youtube.com/watch?v=N_M9A8LeLko&app=desktop

[BillBoost37]

Lack of fluid keeps it from getting into the heater core.

It's time for you to be the eyes of this operation. We can tell you how to fix nearly anything once you are able to pinpoint it. From the way you are typing, I am getting the impression you might not yet be fully comfy around the engine bay. No worries, we can cover that too.

This motor is upside down, see those two silver round spots? Those are called freeze plugs. If there wasn't enough coolant and the temp outside got cold enough, those plugs are supposed to pop out to save the engine from damage. That is one area I want to you look at. There a set in the front and back of your motor. Same place as the picture.


Here's a shot with the motor upright


Next up.. Coolant elbows
These are very common to have an issue with. Especially after getting the motor hot. I wouldn't be surprised if you end up needed to replace the current ones in your motor.
Here's a picture of them in the bracket that holds your alternator. One is dead center of the motor on the passenger side right between the alternator and the coil packs.


Here's what the plastic version looks like when you buy them


Right below that easy to spot coolant elbow is the water pump. Here is a pump


This picture shows the water pump with it's pulley on. Look under the pump for wetness. (This picture does not show a coolant elbow, it is not in pic.)

[Scottydoggs]

that looks like a freeze out plug popped or rusted out. being its dripping down between the oil and trans pans.

if you have some car ramps or a jack and stands, one way or the other to get the car in the air some so you can get under there and really see.

[Draconic]

Lack of fluid keeps it from getting into the heater core.

It's time for you to be the eyes of this operation. We can tell you how to fix nearly anything once you are able to pinpoint it. From the way you are typing, I am getting the impression you might not yet be fully comfy around the engine bay. No worries, we can cover that too.

This motor is upside down, see those two silver round spots? Those are called freeze plugs. If there wasn't enough coolant and the temp outside got cold enough, those plugs are supposed to pop out to save the engine from damage. That is one area I want to you look at. There a set in the front and back of your motor. Same place as the picture.


Here's a shot with the motor upright


Next up.. Coolant elbows
These are very common to have an issue with. Especially after getting the motor hot. I wouldn't be surprised if you end up needed to replace the current ones in your motor.
Here's a picture of them in the bracket that holds your alternator. One is dead center of the motor on the passenger side right between the alternator and the coil packs.


Here's what the plastic version looks like when you buy them


Right below that easy to spot coolant elbow is the water pump. Here is a pump


This picture shows the water pump with it's pulley on. Look under the pump for wetness. (This picture does not show a coolant elbow, it is not in pic.)

The Water pump is fairly new, maybe a a little over a year. The elbow was replaced about 3 months after that with the alluminum ones. But you are right, I am a little uncomforable with the engine bay and since this is the car I need to drive to work every day I am very warry about doing anything that takes me for than a few days. Not to mention I don't have anything more than a nice ratchet set for moving things and taking things a part, meaning I have no lift no way to take out an entire engine. A weekend might be good but I have two kids and the wife is do any day now and we are in the process of buying a new SUV to replace our current one. Very stressful times.

Bill do you have a shot of the rear frost plugs? As Scotty says becuase of where it's leaking I really think the rear plugs may be rotted through or close to it.

that looks like a freeze out plug popped or rusted out. being its dripping down between the oil and trans pans.

if you have some car ramps or a jack and stands, one way or the other to get the car in the air some so you can get under there and really see.

All I can think of at this point is to pull the front end up on the curb and put the eBrake on as I have neither a lift or ramps but will I be able to see the plugs without moving anything from under, especially since the angle will change the direction of the drip?

By the way, thanks so much for being patient with me guys, this was my wife's care from before we got married and I kind of got stuck with it. The other issue I eventually need to fix is the oil pan gasket which my wife says is inside the engine block or really difficult to get to at the point where taking the engine out is required. That doesn't seem right to me. Shouldn't I just be able to take the pan off the bottom of the engine replace the gasket and put it back on?

[Scottydoggs]

oil pan can be done in the car, but the sub frame needs to be lowered, engine held up the bay, by either a hoist or a 4x4 and a chain. or one of them engine holders they sell or rent.

search youtube for grand prix oil pan gasket change, theres more than one how to vid there.

car ramps are kinda cheap to buy. but it sounds like your tight on funds right now. ive done this ghetto deal before for ramps.

[BillBoost37]

The rear freeze plugs look identical. Expect yours to be dirty, but they are indented circles in the block right above the oil pan. A curb has done well by me to get under a car in the past. Only thing is.. it gets tight if the curb is small.

As for the oil pan. That is possible, it's more of a pain in the neck. Oil is easy to add though, so let's start off the the cooling issue that's freezing you. If it's a freeze plug, I'm going to suggest running it past a couple of mechanics to get prices. Someone might be able to sneak in and do one w/o pulling the engine. If so the price shouldn't be huge and that's a talented dude.