Cooling problem

[Wooshie]

I have a problem with my car overheating. I thought it might be the waterpump, but instead of wasting $$$ I decided to flush and fill the system first. Car was running great I thought I fixed the issue. When I was driving yesterday the temp kicked into the danger zone and coolant was gushing out of the resevoir. I pulled the radiator and all the lines to make sure there was no clogs. I put everything back together and made sure there was no air in the system. I let the car idle for about 30 minutes and the temp stayed at 200. I decided to take it for a drive. I was out about 45 minutes with no issues and then when I get about a block from my house the same thing happened. Anyone have any clues? I'm going to get a new thermostat. The radiator was new this year and the waterpump was a reman unit that i put on last year. There is no coolant in the oil and no oil in the radiator. Compression is good on all cylinders. I would prefer to have a good diagnosis before I dump cash into parts I don't need. All thoughts are welcome. I have tons of free time as I'm not really working at the moment.

[Chris]

Did you pressure test the system?

[Mad Max]

The first thing I would do is put your T-Stat in a pot of boiling water and see if it opens up. If that is good then I would pressure test the system and cap after that. If the water pump is bad it will leak out of the weep hole in the bottom of it.

[Wooshie]

Its hard to tell if its the waterpump since I was losing so much coolant from the resevoir. It sprayed coolant everywhere.

[Wooshie]

Did you pressure test the system?
I have not. What do I need to do that?

[Blubird]

are the fans coming and staying on ? i agree with pressure testing it first

[Wooshie]

Yes, fans do come on. Actually it was so hot the fans ran for about 5 minutes after I shut the car off.

[Tarheel'Z']

t-stat sticking maybe?,,maybe some air hiding somewhere,,just throwing it out there

[95formula383lt1]

t stat or cap. pressure tester can be rented from a part store.

[Wooshie]

t stat or cap. pressure tester can be rented from a part store.
I ordered a NIB T-stat from a member on here and I will go grap a pressure tester tomorrow or friday.

[gregrob]

You bled the system right?

Make sure the 2 lines going to the radiator neck are not reversed! (ask me how I know).

The one going to the overflow tank should be on TOP, above the seal of the cap.

The one going to the steam pipe should be on BOTTOM, pressure side of the cap.

[Wooshie]

You bled the system right?

Make sure the 2 lines going to the radiator neck are not reversed! (ask me how I know).

The one going to the overflow tank should be on TOP, above the seal of the cap.

The one going to the steam pipe should be on BOTTOM, pressure side of the cap.

Just went and double checked. They are on right.

[QC97Z]

Sounds to me like a cap or air bubble.

[Wooshie]

Well I couldn't get a pressure tester today, but I did replace the cap. The one I had was rated at 16 LBS and the new one is 18 LBS. It seems to run hotter I'm not sure if its from the cap or that I used water in stead of coolant. I'll drive around town with it for the next few days and if it looks good I'll flush the system and put coolant back in.

[Wooshie]

I havent had any issues with this all weekend. When I lay into it the temp gets to about 220-225, but not any hotter. I think its mostly from running water and not coolant. I got the new T-stat today. I will put that in on wednesday and fill it back up with coolant.

[LT1]

Had the same problem couple days ago, replaced the T-stat and now it runs really cool!

Amazing how cool a new T-stat will make your car run. The one i had in there i put in a boiling pot and it never opend up.

[huntr1117]

Make sure that when you bleed the air out of the system that you ONLY open one bleeder screw at a time.

[QC97Z]

I've always had both open at the same time, and close them up one after the other. Apparently I've been doing it wrong.

[huntr1117]

You really only have to open the pressure side bleed screw on the thermostat housing. I still open them one at a time because that's the only thing that kept my old 94 formula from overheating.