L8Braker

Hello guys and gals, my first post here, so I may as well make a good one. Here goes.

I just purchased a 93 Mustang with a DSS 306 rebuild. The car is a project, but I purchased it because of the parts already installed on the car. In any case the car is running hot but still within the normal range on the gauge(registers on mark above the middle mark). I've replaced the thermostat with a 180, and replaced the fluid with a 50/50 mix, but that did not take care of the problem. When I park the car and pop the hood, I notice you cansqueeze the top radiator hosetogether, so it seems like there is no pressure built up in the cooling system. I replaced the radiator cap and still have the running hot issue. The car has a two core aluminum radiator installed. Is it possible that the cap for that radiator needs a different rated cap? Is it possible that I have an air bubble in the cooling system, this is my 5th Mustang and have a lot of friends with Fox bodies and have never heard of this happening before. I was told to make sure that it wasn't an air bubble to remove the top hose from the heater core going into the firewall and fill the system up until fluid starts running out of that hose. That makes sense to me being it's the highest point in the cooling system, I just wonder if any of you guys have ever gotten an air bubble in your cooling systems? I'm not loosing any fluid, oil looks good, and I'm not smelling anti-freeze coming from the exaust, so I'm not so sure it's a head gasket just yet. I will try this weekend to do a leak down test to rule that out. Does anyone have any other suggestions to try?

Thanks

sivart

what kind of fan does it have? if its mechanical then check the clutch. make sure its a 16lbs rad cap, and u can remove the rad cap then start it, run it up to operating temp, ull see it bubble, then put the cap back on, it should get air out of the system. when u flushed the rad was there any rust?

L8Braker

My bad, yea I should have mentioned when I got the car it had a electric fan, the previous owner did give me the stock fan/shroudand I have since re-installed it, but to answer your question the fan clutch seems to be fine. I didn't flush the system yet, this weekends project. When changed out the thermostat I did remove all of the fluid and replace it with new 50/50. The fluid that came out didn't look too hot, some black crap in there, and the fluid was kind of orangish...wasn't sure if that was the type of fluid or rust as you mentioned.

sivart

it would be dark and and thick, but get some rad flush and flush it out, then put new 50/50 mix back in

vtecwho

i dont know if SIVART is talking about the coolant additive that disolves and cleans the cooling system but i would not use that stuff. it has a misterious way of making the water pump leak a week or so after using it.....

v8tiger

does it run hot in all kinds of driving?

or does it get cooler when going on the interstate?

The fan isnt used after about 40 mph. So if its still getting hot after that then its not the fan.

I would say its a plugged rad. Do a block test. And see if there is combustion in the coolant. Then it will tell you if its a cracked block, heads, or bad HG

Jfsram

Half way on the gauge is about 190deg.

What is your definition of "running hot".

sivart

i was talking about what comes out when you flush it, if it looks like that.....i used the radiator flush when i flushed mine out...no leaking

L8Braker

It runs hot in all kinds of driving, highway, city doesn't matter.

It's running one mark above half way with a new 180 thermostat.