Blk Vert

I’m new to the Fox Body world, but not to working on cars. I just bought a 1991 triple black GT 5.0 convertible with a 5 speed and leather two weeks ago and I love it! My 5.0 (I love saying that) is overheating when it’s at idle too long or in very slow traffic. It gets to the last white line before the red line at the 270 mark. If I’m traveling 10-15 mph it’s fine, but anything less it overheats. The water pump is not leaking from that little hole on the bottom. The fan clutch seems to be working properly after I tested all the different ways given on the web and it has a Mishimoto radiator. The heater core is bad and is leaking if that makes a difference. I don’t know.

Mods:
Edelbrock intake
BBK cold air intake
BBK 70mm throttle body
BBK long tube headers
BBK H pipe
Flowmasters
Mishimoto radiator
A bunch of suspension parts that’s irrelevant

I just bought a Hayden heavy duty fan clutch, Murry heavy duty fan blade(cause it has 10 blades and not 9 and said heavy duty), and a Mr. Gasket 180 thermostat.
My original fan has a bunch of cracks in it and I don’t know what thermostat is in the car right now. It “looks” to be running to cold most of the time and probably has a 160, but I don’t want to ruin my piston seals too early and dump fuel in the engine that’s not necessary. Pictured below is how it runs most of the time.

I also bought a Mr. Gasket temperature gauge radiator cap to check if the factory gauges worked correctly, but it wouldn’t fit my radiator. In the Misimoto version comments section that looks exactly like the Mr. Gaskets said that some people had to pull back the tabs a little bit to make it fit so I might try this, but I’m scared it won’t hold pressure if I do it too much. I guess I can test and reverse it some.
http://www.americanmuscle.com/mishim...iator-cap.html
http://www.summitracing.com/parts/mr...FWsS7AoddiEA0g

I’m open to advice. I’m trying to avoid electric fans. I will not drive this car hard and race it. I might get on it rarely, but not often. This is my coooool car.

If what I just bought doesn’t help I’m going to buy an Edelbrock High Flow Performance Victor Series Water Pump that flows 25% more that stock or something better if it’s not too pricey. I’m open to recommendations that you can provide proof/numbers from being tested. The reason I will replace this first before buying an electric fan is because it will be one less thing I need to worry about in the future, because it will be new. I’m trying to be proactive. Then I will get an electric fan if that doesn’t fix my problem.

Am I on the right direction?

Here are some pictures of my car! I just wanted to share.




Can you tell I'm from TEXAS! lol

mjr46

fix the coolant leak or bypass the core for now and make sure system is topped off with coolant and bleed properly, if all that is done and prob still occurs, if the car cools back down right away once you start moving again, then lack of air flow across radiator is the issue as long as there are not clogged fins from road debris on the condenser if it still has a/c.....also if car has underdrive pullies....ditch them.........I no longer use fan clutches on my rides for the drag they create and are dependent on engine rpm, whereas an elec fan has neither of those issues.

Blk Vert

Ok, I fixed the problem months ago by replacing the clutch fan and fan, but now the problem is back after I replaced my heater core and a/c condenser. Smh Nothing is leaking and I just had the a/c charged.
I'm going to check the level of antifreeze in the radiator in the morning, because I do remember losing a little antifreeze. If that doesn't work I'm going to replace the thermostat with the 180 Mr. Gasket one.
Any advice from anyone?

mjr46

what are you deeming overheating as?? meaning when and at what point on the gauge?

88 orangepeel notch

If you lost coolant, top it off, bleed the air out. Drive it for 15 min. Check level again. Then let us know if it still overheats while idling. If so, mjr's second post is still relevant.

Blk Vert

Hey guys,

I finally had time this weekend to follow up on the over heating issue.
Turns out I was just low on antifreeze.
Which is great news.
The picture with the temp needle almost in the center of the gauge is where it went after driving around and sitting in a parking lot for 10-15 minutes in about 90 degrees Houston weather. (At night)
The picture with the needle after the first mark is on a hot, over 90 degrees day. It normally sit there 90% of the time now.

Heck, I think it's running too cool now. Lol

Anyways, thanks for all the advice.

mjr46

antifreeze doesn't get used up like gas in a car....if it was low, you need to locate the source of the leak or where it went or expect the problem to return once again.

88 orangepeel notch

And if you haven't already learned this, stock gauges are not accurate.

Glad to hear she's all squared away now, time to enjoy it.

Blk Vert

Your right. I think the problem was from when I had a leaky heater core and when I replaced it. I don't have any leaks and I don't have a busted head gasket. I think all is good, but I promise to keep an eye on the temp gauge.

Blk Vert

Yes, I've read the gauges are not that great, but mine "seem" to read ok from the little tests I've ran.

I did enjoy it for one day, thank you.

Now on to the next common problem! Low voltage! Lol