temp gauge

[jfirios]

I just got my car back from DMC and had the engine steam cleaned and all. Driving back to LA was great no problems, then I turned it off grabbed something in my house then went to drive someplace else. The car was hard to start then the temp gauge started spiking, then would drop down to 150 deg. then shoot back up to 260. It seemed to be all over the place. there was no coolant leaking or preasure change in the back of the car, so I am thinking it is the sensor on the engine. How hard is that to replace. I know where it is but looks like a bitch to get to with a wrench. anyone else have this issue?

[Iznodmad]

Sounds like air in the system to me. Did they do any cooling system work on the car while they had it?

[sean]

the green wire going to the sensor in the passenger's side head could be loose.

[stevedmc]

It could be a problem with the gauge too. I suspect it to be either air or a loose wire to the sensor though.

What does the needle do when you whack the binnacle with your hand?


Edit: If it is air in the system, you could make your life easier by installing an auto bleeder. An auto bleeder won't fix leaks, but it will make life easier when flushing and refilling coolant.

[Ron]

Sounds like air in the system to me. Did they do any cooling system work on the car while they had it?+1
Check the level when it totally cools...leave the cap off while it warms up and keep track of how much coolant it takes while watching for any oddities after it settles down at normal temp (eg pushing water out then sucking it dry, oil, air bubbles never stop, etc.)


the green wire going to the sensor in the passenger's side head could be loose.+1 ...but it would also have to be overheated to show 260, of coarse. (Unless it was completely off and/or getting ground somehow.)


It could be a problem with the gauge too. I suspect it to be either air or a loose wire to the sensor though.

What does the needle do when you whack the binnacle with your hand?


Edit: If it is air in the system, you could make your life easier by installing an auto bleeder. An auto bleeder won't fix leaks, but it will make life easier when flushing and refilling coolant.I agree a bad gauge or it's (other) ground making a bad connection might make it lie hot, but with it being hard to start and all, I'm guessing it was HOT...need more info!
IMHO-If he has one, odds are an aftermarket auto bleeder masked a problem and is why he is in this situation. D's come with a bleeder hose coming off of the top of the radiator (coolest fluid) going straight to the tank, not right after the thermostat (hottest fluid), then right back into the engine...does more harm than good, unless you don't know how to properly bleed the system when adding/changing the coolant...you have a problem if any air gets in afterwords. We were discussing this on .com right before the crash and I'm all ears (in another thread) if there is something I have wrong/missing...

[sean]

+1 ...but it would also have to be overheated to show 260, of coarse. (Unless it was completely off and/or getting ground somehow.)


Well Im just assuming that things worked fine before the engine got steam cleaned so to me the only thing that got fiddled with between then and now was the engine bay when cleaned. I suppose its possible the gauge just so happens to fail after the engine gets a steam cleaning though.

[stevedmc]

IMHO-If he has one, odds are an aftermarket auto bleeder masked a problem and is why he is in this situation.

Yep.

[jfirios]

well, i did the test that danny over at DMC CA suggested. When the car was completely cold, first thing in the AM. I removed the cap on the coolant tank, and made sure there was about half full of coolant, which it was then started the car with the cap off and made sure that there was fluid circulating through the tank which it was doing no porblems there. Which lead him to believe that it is a sensor issue. Yes it was working fine before the cleaning. I also while the engine was cold checked the wire on the sensor, it seemed to be fine but i moved it around just in case it was touching something. I have now driven it for a while, going about 75-90 for 15 min drives covering about 20 miles or so. the temp moved up normally and then stayed at the 220 line not really going over but would drop down every so often. I have done this twice today to test it and both times seems to have the same results. When the temp did spike and jump all over the place, there was no leaks or burst lines that would indicate a true over heat, or steam pouring out of the engine bay. The fact that it was completely erratic leads me to believe either there happened to have air in the line, or the sensor is going. All they did at DMC was do an oil and lube, top fluids, and replace the steering bushing and one broken bolt on the exhaust manifold. Either way I am going to have the cold start replaced and the sensor replaced monday.