Hi everyone, new here but have been lurking getting a lot of great information. I took the plunge yesterday and bought a 89 iroc with a 350tpi. Car is defenitly a project and I am definitly new to working on cars just something I always wanted to do. Anyway. I was told when I bought it the thermostat was bad, I drove it home with no problems about 30 miles but when I got home I noticed the coolant overflow was boiling. Anyway today I got under it drained the coolant (it was just water) then replaced the temp sensor on the front of the block and the thermostat. I guess the tstat was bad, there was not one there! Anyway cleaned up the old melted gasket stuff put the tstat in. Put it all back together and then was about to refill with 50/50 coolant...annnnd car wont start. No crank. Nothing. Only thing moving in the car is the temp gauge which is immediatly pegging out. Im sure I screwed something up but hoping to get pointed in the right direction. Thanks in advance.

 

Did you forget to plug something back in? Like the MAF or IAC?

The temp gauge will peg when you turn the key from run to start, it's a gauge test feature to let you know the gauge is working. The same idea as all the dash lights coming on briefly when you start the car. Now if it stays pegged, you might want to find the green wire on the driver's side of the engine, down by the exhaust and steering shaft. It should be plugged into a sensor in the cylinder head, if it comes unclipped and melts to the exhaust, or gets pinched and the wire shorts to ground, the gauge will max out.

Usually a tstat will be missing because someone removed it trying to fix an overheating problem. Look under the car, you should have a plastic flap across the bottom of the radiator support that hands down about 6" towards the ground, and stretches the width of the radiator. If that flap is gone, the car will overheat.

If the engine has been overheated often enough, it could have locked up, or may otherwise be junk. Hopefully it's just a dead battery, or a harness that was left disconnected, but the "bad thermostat" is a red flag from the previous owner.

 

Thanks for getting back to me. I could have sworn i hooked everything back up, only disconnected two harnesses. Battery was my first thought as well but I had left my meter at work. Saw the car a couple times, never had a problem starting and even after I drove it home and it got hot, I had it on again after it had cooled down, really hope nothing seized. Going to be a long day thinking about it till I get back tonight, I will update if I find anything.

 

Go get a radiator cap to fix the "boiling" ' "overheating" issue.

Temp gauge pegged during start = the factory designed it that way; it's the same as the old "bulb test" for the idiot light, which was designed to come on during start so that the big nut that goes between the left front seat and the steering wheel would notice it if the bulb didn't work so they would IMMEDIATELY replace it. (yeah I know, like that really worked...)

The no-crank sounds like a VATS issue. Might want to do a quick search on that. Maybe even, just clean off the contacts on the key; or even, if you got more than one key, try another.

 

Wow, I had no idea but the VATS does sound like whats happening, and the fact that the dash lights up on accessory every fifth or sixth time when turning the key and then others not at all. It does have an aftermarket steering column in it, and the key is sticky, wonder if the whole ignition is a problem. Of course it wouldn't happen until it was in my garage. Thanks again for the help, I will make sure to update after looking into all of your suggestions.

 

Check if the security light comes on and stays on with the key in the ON position. If it is then its a Vats issue

 

Got home and taking a loom, battery is good now it is cranking today when it wasent last night. Just the starter clicking and the sad sound of nothing. Both sensors I unplugged to do the thermostat are plugged back in. At a loss what could have changed doing this small job. Car never gave Any indication of having trouble starting. Dont even see an area where I could have screwed anything up in the area of the tstat. Heh welcome to messing with my car I guess.

 

On my IROC, I had a temperature issue, and discovered that the wrong water pump had been installed on the car. serpentine belt cars run the water pump in the opposite direction compared to old-school V-belt cars. Really easy to be given the wrong pump, and not realize it’s not doing the job.

 

water from overheat probably grounded something out ok when dried out.

 

Wow I found it...got so worked up over the thermostat got to focused...the chassis ground from the battery had broken off. Started right up. Of course whem I went to refill the coolant it all came pouring out of the new tstat...guess my seal was not right?

 

Pop the waterneck off, clean the tstat box on the intake. Make sure the stat drops into the relief, and clean the gasket surface of the waterneck. Use a good quality gasket, or a cheap gasket, if the surfaces aren't flat and smooth, a skim of RTV on the gasket will help it seal.

 

Just a FYI, the thermostat housing can be prone to cracking from over tightening. Sometimes just a hairline crack at the base of the tube, but they will leak under pressure. Good luck and have fun with your car.

 

Hey Guys, just dropping by. I have success. Got a better thermostat and a matching mr gasket gasket for it, used the little bit of rtv, no problems filled the coolant, ran it around some did not get hot at all. Something has changed, i have a very very low idle and it stalls out now, was not happening before, drives fine though. I will dig through the forums and tackle that next. Thank you to everyone who responded and helped me out, I appreciate you taking the time even for a panicked newb.