Ninety3Coupe

I just got it yesterday. Needs some paint but is remarkably straight and has 91,xxx original miles. So happy!

Except the thing overheats. Right, wrong or indifferent I bought a 160 degree thermostat and replacement radiator (standard) and replaced them both this morning. The original radiator had 2 pinholes and I knew it overheated when I bought it.

The odd thing is it takes about 30-45 minutes to overheat. Until then it runs very, very cool and then bam! Within 5 minutes it is at 80% on the gauge.

It has pullies, but I do not know the maker. My first thought is to find stock pullies and change them. I see coolant moving in the radiator so the pump should be fine. I made sure to add new fluid, turn it on, wait for the thermostat to open and then top off the radiator when I did it this morning. Should be full.

Please help! I want to be excited for this car (I have wanted a coupe since 1990 when I was in high school!) but this problem is ruining it for me.

Thanks for any and all help!

rtintwo

When is it overheating? Stop and go, highway or idle?

Double and triple check your fluid level.

Rent a laser thermometer from a parts store. Get it to over heat(dont go crazy and let it over heat for a long) Use the lazer on the thermostat housing and see what the temp is, if it gets to 220 then yes is is over heating and not a gauge problem. Do this and report back. Need to know the engine is actually overheating first and you arent fighting a bad sending unit or gauge.

Ninety3Coupe

Darn. I even OWN a laser temp gauge. Sometimes the good ideas are right there in front of you... I will do this tomorrow if I can get a chance to get away from work.

I went to Auto Zone and rented a pressure tester. I took off the cap and pumped the radiator to 16 degrees (the caps rating). Within 30 seconds it gradually dropped 1/4 to 1/2 psi and then leveled out completely for a minute and a half and stayed put. I pumped it to 19 psi and had the exact result again.

I checked the cap and it was a goner. Wouldn't hold past 7 psi so I returned the tool and bought a new cap. The guy behind the counter lead me to believe this was all a very good sign of it not being a cracked head or block or a head / intake gasket. Is this accurate? If so, thank God!

He also recommended replacing the coolant "switch". It was 10 bucks so I bought it. Looks like it is on the drivers side of the manifold, up front with a red wire going to it. Easy.

Any more info or insight? Anyone else wanna tell me it doesn't sound like something really bad now?

nitrous_bob

i'd just get rid of it...coupes are ugly anyways







haha...congrats

tell me this though.... did the new stat have a little check ball in it ?

i doubt its serious, you just need to figure what the issue is. possibly pump is moving coolant...but just not enuff. has it been like 105* every day since youve had it too ?

tohoopty

first thing id do is get rid of that 160 t stat

rtintwo

Not a bad idea to do but the problem happened before the 160 tstat was installed.

Ninety3Coupe

Lesson learned on the 160 thermostat. I will be changing it. (Roy, remember, more is not always better...)

Nitrous Bob, that was hilarious. Ya had me going until I saw your signature pic! Thanks for the chuckle.

RTINTWO - TOOL is an awesome band. Please tell me that is the reference. If so we may just be friends. 14 concerts and counting so far. Ordering the TOOL sticker was actually my first "mod"

The Problem - I have not had time to drive it and see if it overheats yet, but I do know the timing is advanced (info from previous owners friend) and have heard that can be a culprit. Don't know where it is set at, but I will tonight or tomorrow and I will put it back to stock. 10 degrees, right?

I replaced the switch or sensor on the manifold (drivers side near front - red wire going to it with elbow on it) - with the nose of the car up a little. As I unscrewed it coolant came a dribblin'. I'm thinking that an air pocket is not the cause right now. I will be re-burping the thing just to make sure.

The next step is still trying to find some stock pullies. Sheesh they can be pricey!

Then I guess is a new HD water pump. Don't wanna have to do it (just had it all apart!) but I may just have to. Makes getting to the thermostat again easier too I suppose.

Any other info or ideas? Anyone question or want to modify my order / reasoning?

Thanks again all of you.

Except Nitrous Bob. That guy's weird! (j/k dude!)

rtintwo

Yup you got the reference. I have only been able to see them once, life has a tendency to get in the way.

It wont hurt to change the tstat again but sense the problem started before this one was in it wont fix the problem.

Hit up craigslist for the pulleys it should be easy to find a set for cheap on there.

I would hold off on changing the pump until you know the problem is still happening and you get your lazer on it.

Ninety3Coupe

Ok, still haven't gotten to drive it, but I let it idle for 30 minutes and it never got above 136.3 with my laser on the thermostat housing (instrument gauge read dead-nuts the same). It WILL NOT overheat at rest, but...

There is a chance that when I tested the cap the other night and it turned out bad (wouldn't hold above 7 psi) that replacing that fixed my issue. I just can't drive it to see yet, but I doubt it did the trick. Anyone disagree? (Work too many hours and parking is impossible here. Miss a parking spot and it has to be parked on the street in a gang neighborhood...not worth it!)

I tried to check the timing by pulling that little plug, and it looks like the idles about 12-16 degrees. I plugged the plug back in and checked again and the timing appears to surge a little bit and I can't get a reading. The car idles like it has a cam but I am almost POSITIVE it does not. I noticed when I first looked at it to purchase and tonight, but not other times I have driven it. Inconsistent. What is this about? Related to heating perhaps?

I think no matter what I am going to throw these aftermarket pullies off the end of the pier. I checked the voltage at idle (about 850 rpm or so) and it is only 12.52 (jumps a bit) and goes up to 13.98 when revved just a little. The pullies are slowing stuff WAY down, right? May lead to my issues...?

Sorry to be such a pain in the butt guys. The problem is I actually do know a bit about cars and all these issues are just fricking weird. I really appreciate any and all comments!

Ninety3Coupe

I DROVE IT...

And the gauge went to 250-260 (one line below RED) on the instrument panel. I jumped out of the car, took my laser thermometer and shot the thermostat housing. 215 degrees.

Keep in mind it was well over 90 degrees out today.

I then jumped on the freeway and the panel gauge dropped to just below halfway.

The gauge is wrong and my temps are fine, right? If so, AWESOME!

Also, I assume that I need a new fan clutch and to ditch those $@*!&@$ pullies for the stockers and I should be good. Any ideas on the gauge reading wrong?

Another odd thing popped up however. There was a horrible accident on the freeway and we all came to a stop - dead stop - for about 15 minutes at the hottest point of the day. The gauge got the highest it has ever been (just below RED - I'm guessing 220ish) and the A/C stopped blowing cold. After we started moving again and the temp indicated lower it blew cold again. Ideas here?

I read up on many, many possible causes of the rough idle and will tackle them this weekend. It idled great today with no sign of this mysterious "big cam" idle. Salt and Pepper shakers and TPS voltage is where I will start.

Thanks again to everyone! You guys have been awesome.