Grand Prix Overheats & Service Engine Light is on

[acidbern]

Ok, i'm new here but i hope someone can help me. I have a 97 Grand Prix GT, its the 3.8 w/o the supercharger. It has about 194,000 Miles on it as well.

The problem started out as the temp guage going WAY up. Then all of a sudden it would drop back down to normal. Plus, i'm loosing coolant somewhere, cant find any puddles, or major leaks. Ok, so the temp thing Sounds like a thermostat. Ok, cool, i replaced the thermostat. That didnt stop it. So i went back and replaced the water pump. That didnt fix it. Now its to the point that once the engine starts heating up, it goes WAY up sometimes even into the red. Then occasionally i'll drop back down to normal. The drop is REALLY fast. then it starts rising back up again. It still does this even if i'm on the highway. Last night i replaced the thermostat again just to be sure, still no effect. We let it run in the driveway, and the temp guage went to about half way and sat there. Once i got in and gave it some gas it started going up. Once it got up towards red, we saw steam coming from the engine. When we looked, we found that coolant was actually spraying out in a very fine mist from a spot thats kinda behind some stuff so we cant see EXACTLY where it is. But its not supposed to do that, lol. And we're not sure what part that is right there. If you are looking at the engine from the front, on the left side straight up from the water pump, there is a small black box looking thing that is sort of connected to i wanna say the head?? Its all sealed with the head gasket anyways. Anywho, there is a black little elbow looking thing. We're not sure what it even is, but the coolant is either spraying from the back side of that elbow, or from the seal thats right by it. I'm just not sure what it is or where to go from here. Any help that anyone could give me would be great. If you need more detail or something to help, please ask. Thanks

AcidBern

[pottsy710]

if it's a little elbow black pvc tube by the serpentine belt, then you have to go to the dealer to get that part, i had the same prob with my 97 gt, it's about a 5 dollar part and when mine split it actually threw the belt off. it's not hard to replace, it just pops out (it's only held in by a couple of o-rings) and you pop in the new one and problem solved.

[acidbern]

Was that piece causing your engine to overheat and lose fluid as well?? And do you know what its called so i know what part i'm asking for???

[pottsy710]

yeah that piece did cause my car to overheat but more apparent was my loss of all electrical power cuz the belt was thrown, now mine split along the outside toward the left side of the car (if you are standing on front facing it). if the piece i'm talking about is split it's called a By-Pass Hose, and the part number is 10182356, and it's between 5-10 dollars, the unfortunate part is you HAVE to go to the dealer to get this part, no auto parts stores, like auto zone and even napa, carry the part.

[richtazz]

The elbow mentioned is GM part #24503423, it runs $8.37 dealer retail and it includes the o-rings. IF that's not leaking, then you may have a cracked upper plenum, a common problem with 95-99 Vin-K 3800's. They are available aftermarket for around $150 or so.

[acidbern]

I think thats it, =) I did some more digging and it appears to be leaking from that bypass tube, it's not split like yours was, but I think the o-rings are bad or something. Neways, i topped off the fluid again, and ran it w/o a thermostat at all, and the temp guage stayed between 140 and 160 most of the time, but it still seeped out from that bypass tube rather than "sprayed" out of it. Its my understanding that w/o the thermostat in it, its just flowing free, and not sending much fluid through that bypass. I went to the dealership, bought the part for 8 bucks, he even gave me some diagrams to help replace it. Apparently i have to remove the altenator and the tensioner assembly and it fits into there. I hope it just sticks in there and i dont need some special tool to make it stay. Anyways, thanks for the help, i'll post again when its done =)