9.0

really awful
Typical Repair Cost:
$828.00
Average Mileage:
128,595 miles
Total Complaints:
10 complaints

Most common solutions:

  1. not sure (3 reports)
  2. replaced manifold, gaskets and thermostat (3 reports)
  3. replaced water pump, manifold, gasket, oil, coolant, thermostat (3 reports)
  4. change the gaskets (1 reports)
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problem #10

Jun 172011

Grand Prix GTP 3.8L V6

  • Automatic transmission
  • 101,262 miles

Pontiac knew about this problem a long time ago and instead of doing a recall on it because it wasnt a safety issue some people have had to totally redo their engines. No wonder pontiacs gone you want us to buy american and we should buy american but after this fiasco I will go back to driving Hondas or Toyotas.

- , Ogden, UT, USA

problem #9

Aug 302010

Grand Prix GT 3.8L

  • Automatic transmission
  • 163,530 miles

Cylinders 4 and 6 filled with coolant and the engine shut off. Temperature gauge never read over 210 degrees. I incorrectly assumed that the head gasket or head had warped and I took both heads off of the engine to rebuild it. I checked for warp with a steel rule and did not see any warpage, so I bought new Fel-Pro gaskets and reassembled the engine. It lasted for 6 days and the same thing happened again. This time I took off the head covering cylinders 2,4,&6 and took it in to a machine shop to check for warpage and to pressure check the head. The machinist only shaved off 6/1000 of an inch and the pressure check came out good. I reassembled the engine, started it up, and this time it only lasted for 20 minutes before all of the coolant was sucked up into the same 2 cylinders. I have since been told by an retired-mechanic at our local Pontiac dealership that most likely the problem is in the intake manifold gasket set up and not in the heads. Still do not have it working but will try again when I get the full scoop from my friend as to what to do the fix the problem.

- , Canton, Georgia, USA

problem #8

May 142008

Grand Prix GT V6

  • Automatic transmission
  • 120,000 miles

PONTIAC SHOULD BE RESPONSIBLE FOR THE PROBLEM WITH THE INTAKE MANIFOLD CRACKING AND CAUSING THE COOLANT TO GET INTO THE OIL........ WHY DID THEY MAKE THE INTAKE GASKET PLASTIC IN THE LATE MODELS THE TEMP GAUGE INCREASING AND DECREASE AFTER ONLY DRIVING A MILE DOWN THE ROAD, THE VEHICLE RUNS ROUGH AND TURNS OFF PERIODICALLY. PONT NEED TO GET WITH THE PROGRAM, YOU WANT US TO BUY AMERICAN BUT YOU DON'T ACCEPT YOUR FAULT AND EXPECT YOUR CUSTOMER TO PAY FOR YOUR MISTAKE IN ENGINEERING THE 98 3800 V6 SERIES II ENGINE........................

- , Elkhart, IN, USA

problem #7

Jan 232008

Grand Prix GT 3.8L

  • Automatic transmission
  • 101,000 miles

Very common problem with the 3.8 Series II motors. It is a manufacturing defect in the thickness of the walls of the water and air ports that run through the manifold. Heat and Dex-Cool break down the plastic and failure is only a matter of time. I replaced the 195� thermostat with a 180� (a 170� is available however I do not recommend it this will cause other problems) and purchased a replacement manifold on e-bay for $69.95, free shipping and lifetime warranty! Did the work myself, took about 3 hours. The replacements are designed with thicker walls so they will last longer. I was lucky my failure caused an external leak. BTW a lawsuit was just finished regarding this problem and some folks can get a buck or two back if you are eligible check for a settlement from California on Google.

- , Carlsbad, CA, USA

problem #6

Jul 102007

Grand Prix GT 3800 V6

  • Automatic transmission
  • 154,000 miles

Excessive over-heating. Dexcool looks like coffee. Radiator fans not running. Fans run with 12v applied, bypassing relays. Replaced relays..nothing. Don't know where the temp sensor is. Went through 3 water pumps in 10 years. Have not replaced manifold gasket thank God. I will continue driving this vehicle until it seizes up. I feel lucky to have a Pontiac last 10 yrs 154k miles. For the last 5 years I have had a hole in the exhaust resonator about the size of a golf ball. CAR SOUNDS GREAT!!! I call it the free Flowmaster.

- , Cincinnati, OH, USA

problem #5

Jun 162008

Grand Prix GT 3.8L V6

  • Automatic transmission
  • 145,000 miles

I must say I have owned this car for 10 years and truly have not had a bunch of trouble, but now it is at the point that some of the repairs could possibly cost more than the car is worth!! I have replaced 2 alternators, 1 torque converter, one electric window button, and now will have to spend 450+ to fix this problem. Also, the Delco coolant really makes for a gummy mess and I feel that is why the car runs hotter at times. I will also have to flush the radiator when I get the gasket replaced.

- , Langford, South Dakota, USA

problem #4

Nov 182007

Grand Prix SE 3.1L

  • Automatic transmission
  • 129,537 miles

I have a 1998 Pontiac Grand Prix SE and I had to have my intake manifold replaced at about 129,000. One day I was in a drive thru and I had the break applied and the enginge was revving really hard on its own, all of a sudden my car just shut off. I was ale to get my car to start back up and make it home (I was about a half a mile from home) but on the way my car quit and I had to start it back up again. When I brought it to the shop they told me I had to replace my intake manifold and they also advised me my oil was full of antifreeze. I had it fixed about two weeks ago and now I am having problems again.

- , Brooklyn Park, MN, USA

problem #3

Aug 252007

(reported on)

Grand Prix GT 3.8L V6

  • Automatic transmission
  • 166,000 miles

Typical for this Pontiac engine. Leaking more and more coolant as time rolls on then finally... poof... it just quits. Told by GM mechanic that it is a more than 'typical' problem known by GM for some time, but nothing is being done about it. We just had the same problem fixed on the same engine in our 2003 Montana, which fortunately was done under warranty. Anyone know of a permanent fix to this problem?

- , Shawnee, KS, USA

problem #2

Feb 162007

(reported on)

Grand Prix SE 3.1L V6

  • Automatic transmission
  • 85,625 miles

The first time I noticed the temperature gauge spiking at almost 125C and then within minutes dropping back down to 40C I took the car in immediately. My mechanic said the water pump is leaking and it was replaced for $400+ and then a month later the symptom (engine temperature spiking) was noticed again. Now the cost is $900+. This is ridiculous. Pontiac should have really published this knowledge if it could lead to critical quality issues with their products!!

- , Mississauga, Ontario, Canada

problem #1

Jul 282006

(reported on)

Grand Prix 3.8 L

  • 120,000 miles

Apparently, there is a design flaw in the 97-98 models of the Grand Prix in that the intake manifold/manifold gasket is plastic, and over time, will crack. Some symptoms I had was the engine overheating, sometimes running at 230 degrees after less than a mile of driving, and the engine idle sound/frequency was much higher than normal (normal sounding: bass, new sound: soprano). When the manifold cracked, it caused a coolant leak, possible water pump damage, and who knows what else. I spoke with a mechanic about it, and he said that Pontiac knew about the design flaw, and that it would normally crack around 80-100k miles, but there wasn't enough intances of the problem to warrant a recall, basically obsolving them of the financial responsibility. They, Pontiac, fixed the problems in future models by making the manifold out of metal. Unfortunatly, there is no easy way around this problem, except to replace the manifold completely.

- , Raleigh, NC, USA