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95 riviera overheating

06-15-2009, 05:45 PM
earlier this week i posted about my riviera overheating and was told it might be the heater core but i have gotten different feedback from another mechanic, who says different. Whats happening with the car is that it is overheating and coming out somewhere in the back towards the middle. The car doesnt leak antifreeze while driving but when it gets to the red zone all the pressure builds up and its coming out from the back end, my guess is the spout near the heater core itself. The raidiator stays cool but the top hose going to the engine is hot.The radiator itself is still fairly new, about a year old now. The antifreze isnt pushing out the radiator into the engine where the thermostat is located. I just put a brand new thermostat on and still have the same problem. Im wondering if it really is the heater core or is it something else.

06-15-2009, 05:48 PM
also there is no puddle of antifreeze inside the car on the passenger side which someone told me is an indication the heater core is bad, thanks in advance.

06-15-2009, 09:14 PM
Are the fans running when it get's into the "red zone", or will one fan run when the AC is turned ON?

06-15-2009, 09:28 PM
yes both of the fans turn on when it goes into the red zone but it still overheats because the coolant isnt circulating properly.

06-16-2009, 03:17 PM
The antifreze isnt pushing out the radiator into the engine where the thermostat is located.
Ok, first of all coolant flows from the thermostat housing to the radiator to be circulated & cooled, then flows through the bottom hose of the radiator back to the water pump inlet housing to be pumped through the engine. You need to find where the leak is, if the cooling system is not completely full at all times and all air purged, it will overheat.

06-16-2009, 05:55 PM
the coolant in the radiator is topped off, so i will try to find the leak, hopefully its just the hose has a hole in it or somethingg, will try later on in the week and repost as to what happens , thanks for the response.

07-01-2009, 12:38 PM
Ok heres the diagnostic of the car from what I can visually see. The car is overheating frist off. I did a flush checked the hoses and everything seeems fine. The car will not overheat when idle in the park position, the gauge will stay right under the red zone. When I drive it however it will overheat. The coolant level is topped off and doesnt leak until it builds up enough pressure to shoot out somewhere in the back. I was told its the spout near the heater core. The heater is not faulty itself. The thermostat is new the water pump is fairly new maybe a year old now. The coolant itself is not circulating properly, it sits in the engine and does not pass through my thermostat. The oil is also burning rapidly, checked the dipstick and the oil level was low. I added 2 quarts to make it heat up so a mechanic could look at it. Unfortunately when it started getting to the red zone the car shut off. When I took the oil cap off it was smoking and the oil was all burned out. Theres not visible external oil leaks. The car idles roughly as well it the nozzle goes up and down and doesnt stay in a fixed position. I also heard faint knocking under the engine when i come to a stop but it would disappear when I drive. I heard that gms have faulty intake manifold gaskets for my year and model and are facing a lawsuit for it actually. I just want to make sure the intake manifold gasket is faulty before i make any more repairs because its 800 dollars from a rough estimate.

07-01-2009, 02:31 PM
I assume you have the Series II (VIN-K) engine, if so Click Here ( more info. The UIM is the problem, not the gaskets, but it is best to change UIM & LIM gaskets while you are at it. Sorry, but if you have a faint knock @ idle, it's too late to save the bottom end, you will need a new crank kit which consist of crank, rod & main bearings. The more the engine runs in it's present state, the more damage it causes.:crying: BTW, I moved your latest thread to your original thread on the same subject , to help keep everyone on the same sheet of music.

07-29-2009, 01:11 PM
are you able to tell me the name of the piece i need? I tried autozone oriely and nappa auto parts stores. They say that they cant get the piece i need and need to get it through the dealership. Is it called an EGR tube? I called GMC and they say that part is either discontinued or that they are not finding anything that matches what i am telling them. He asked me does the tube connect to the egr valve and I have no idea im not a mechanic myself lol. So can you tell me the exact name of the piece so I can order it, been at it for weeks and still no luck, id hate to have to replace the whole manifold itself just to fix the car.

07-29-2009, 01:16 PM
better yet if you have a picture of the part itself can you post it, that would be a lot more helpful so when i go down there i can look for it.

07-29-2009, 07:32 PM
Click Here (
1995 BUICK RIVIERA V6 - 3.8L (231 CID): GAS: FI: N: K Upper; Designed specifically to work with Dorman OE Solutions Intake Manifold Gaskets only.

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