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93 Grand Prix stalling, running hot, coolant leak

T

thehollowaytape

New member
Okay, I am hoping this will get more attention here..

I am really needing some help with my 1993 Grand Prix LE.. it has the 3.1L MFI engine.

My problems, that I know of, are as follows:
High idling temp, though it goes down. (Gets to almost 240.. I'm thinking water pump maybe..?)
There is a coolant leak right under the t-stat housing. Can anyone please tell me what might be leaking?
I think my belt tensioner is bad. It wobbles when running, not just the pulley but the whole arm.
My car will periodically stall and/or hesitate like crazy when accelerating from an idle.
My car will periodically stall when turning from an idle.

Any help would really be appreciated..

Edit: Also, forgot, I usually average 12mpg...
 


1. I would change the thermostat, as the leak at your housing is most likely due to the t-stat gasket having gone bad. For an entire $10, you may as well change the whole t-stat out (which should come with a gasket anyway) so you can rule out the possibility of a bad t-stat at the same time. Your high idling temps may very much be due to that leak (allowing air into the system). Make sure you completely bleed the system of air after you're done replacing the t-stat, too.

2. If the whole arm is wobbling on the tensioner, then yes, I would replace the whole thing. It's not very expensive, and it's pretty common for them to go bad as they get up there with age.

3. The stalling and poor gas mileage issues can be caused by any number of things, which can be divided into 2 categories; electrical, or fuel related. The car is either not burning the fuel efficiently due to something not firing correctly in the electrical system, or it's dumping too much fuel due to a something not operating correctly in the fueling system.

a. I'd first start out by getting all three ignition coils and ignition control module tested for free at any number of parts stores. Then, change your spark plugs and plug wires (it's cheap enough to do that I wouldn't even bother with checking them, or be concerned with how recently they were done). The computer is another possibility here, but I'd leave that for last, as it's not common.

b. If you have access to a multi-meter, check the resistance on the fuel injectors, and make sure they're within spec. Using a fuel pressure gauge, I'd also check what kind of pressure you're getting at the fuel rail. Leaking fuel pressure regulators are also very common on these motors with age. I'd also change out the fuel filter since it's only around $12, and should be done once a year or so, anyway.​

Everything mentioned above is very common for failing on the 3.1s. I'd start there, and see what you find first.
 
GM fan pretty much nailed it.

#1 Replace the entire belt tensioner. Get the whole sub assembly with the arm, spring and pulley. Also, a new belt is probably in order.

#2 Put a new 185F thermostat and thermostat gasket in. While you’re doing that make sure the thermostat housing itself isn’t damaged.

#3 SeaFoam that baby, then replace the spark plugs.

Get that stuff done, and get back to us.:th_winking:
 
Well this weekend I replaced the t-stat, flushed the radiator and put all new coolant in, got a new radiator cap, and changed the belt tensioner assembly. The spark plugs are nearly new.

I drove it up the road to get the coolant flowing and coming back it started stalling again. Went and got a new fuel filter and replaced it, drove it home fine. Was about to go to Advance to get a brake light and it started stalling again, so I kept having to start it in neutral and go until it died to get it back home. Fuel pump?
 
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did it fix the leak? i was thinking intake gaskets. would explain all of it. the 3.1, and 3100 are famous for intake gaskets, and t-stat housing bolts to intake. might be leaking coolant internally as well as externally. increase in vacume could suck coolant into cylinders creating stall. coolant don't burn to well.
 


Wow your car is in a world of hurt.:th_skull: One thing is for sure you need to get the coolant system fix before worrying about anything else. I’d hose the engine compartment down to clean it out, hose it down after the engine hasn’t run for an hour and stay clear of electrical stuff. Then run it in place and see if you can tell where the coolant is coming from.
 
Well, it's going into the shop tomorrow. We'll see what they do, I'm not advanced enough as far as fixing cars to do any of this lol. I'll let you guys know what happens though.
 
oh man.. sorry to hear that, my 92' has the same issues, however, new water pump, new t-stat, tried to drive her home.. she decided to break down in front of a coffee shop..


however my thing is. someone tried to remove a bad heater core, and did a real (insert colorful adjective here) job on the car, meaning leaks like a collander.. so my floors are soaked, but... at least I got her home thanks to a Chevy Blazer.
 
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