Would a stuck t-stat cause a service engine soon light?
#1
Member
Posts like a V-Tak
Thread Starter
Join Date: Sep 2004
Posts: 99
Likes: 0
Received 0 Likes
on
0 Posts
Would a stuck t-stat cause a service engine soon light?
My temp gauge has been acting strange the last few days and now the service engine soon is on. Would a stuck t-stat cause this? or is it something else? by I mean acting strange is that when you start the car it stays at the bottom for like 5 minutes and then shoots up to normal temps and then shoots back down to the bottom again after driving awhile. If the t-stat was bad I know it would overheat but if it'* stuck open it wouldn't read temps accuarate. I checked the ECT and it seems fine, no shortings from what I can see but wouldn't that come up on diagnostic since it'* electrical?
#2
Senior Member
Certified GM nut
Join Date: Feb 2003
Location: Georgia
Posts: 2,095
Likes: 0
Received 0 Likes
on
0 Posts
Well there are actually two sensors. One for the gauge and one for the computer. Funny huh? They're actually two different parts too so you can't swap them. I know when my engine was put back together one of them was left unhooked nad it did set the check engine light. Plugging it in fixed it. The car was only running for about 1min before this was checked and fixed so I'm not sure what effect it would have. So in any case, yes it will set the light.
How quickly does the gauge move? Is it gradual as if it could POSSIBLY be actual temperature changes or is it really quick?
How quickly does the gauge move? Is it gradual as if it could POSSIBLY be actual temperature changes or is it really quick?
#3
Member
Posts like a V-Tak
Thread Starter
Join Date: Sep 2004
Posts: 99
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by DrJay
How quickly does the gauge move? Is it gradual as if it could POSSIBLY be actual temperature changes or is it really quick?
#4
Senior Member
Certified GM nut
Join Date: Feb 2003
Location: Georgia
Posts: 2,095
Likes: 0
Received 0 Likes
on
0 Posts
Yeah that really sounds like a sensor problem. Just to make sure you don't have a freak problem next time it drops to the bottom (cold) pop the hood and grab the upper radiator hose, should be pretty hot. In anycase I think the sensors are rather cheap and fairly easy to get to. Might consider just replacing them both if you have some spare moolah. On a side note, if the one the computer listens to is failing also it should come along with a few warm-start issues. If thats not happening it may be safe to assume only the one to the gauge is failing, in which case I think its more of an annoyance than a problem..but I could be wrong.
edited cause I can't friggin type
edited cause I can't friggin type
#6
Senior Member
Certified GM nut
Join Date: Feb 2003
Location: Georgia
Posts: 2,095
Likes: 0
Received 0 Likes
on
0 Posts
The 'grab the hose' test I said earlier should determine if it is infact the sensor.
Also, its possible that the PCM doesn't listen to, nor care, about the sensor that the gauge is going off. Maybe it only cares about the one its listening to directly. I can't remember which of mine were disconnected, but it did set the check engine.
Also, its possible that the PCM doesn't listen to, nor care, about the sensor that the gauge is going off. Maybe it only cares about the one its listening to directly. I can't remember which of mine were disconnected, but it did set the check engine.
#7
Member
Posts like a V-Tak
Thread Starter
Join Date: Sep 2004
Posts: 99
Likes: 0
Received 0 Likes
on
0 Posts
The main thing I'm worried about is that the mechanice I took it to a few days ago said my waterpump sounds like it'* fixin to go out and if that does go out and my temp guage aint working right I could blow my engine or cause some serious problems due to overheating. I think I'm going to change the t-stat first just because it'* a easy and quick job and see if that fixes and it that don't then it must be a sensor. It probally still has the stock one in it anyways.
#8
Senior Member
Posts like a Turbo
Join Date: Jul 2004
Location: Woodstock Ill.
Posts: 214
Likes: 0
Received 0 Likes
on
0 Posts
Just my $0.02 FWIW, but I think the sudden change is caused by a stuck thermostat suddenly unsticking and opening quickly. I'd change that first and see what happens.
#9
Senior Member
Certified GM nut
Join Date: Feb 2003
Location: Georgia
Posts: 2,095
Likes: 0
Received 0 Likes
on
0 Posts
Sure if you want, but like I said you can save yourself the time and money just by feeling around. Grab the top hose, bottom hose, and just generally feel around. See if it feels like 200deg or 100deg..Either way, hope it works out.