Thermostat

[s&k stangs]

I scanned through previous posts on this topic, but didnt see exactly what I was looking for. My 91 gt is bone stock, aside from K&N. The coolant is disappearing. I seem to have add coolant every couple of weeks or so. There doesnt appear to be water in the oil, and I havent found any puddles on the driveway. I only have a stock temp gauge and even at operating temp, the needle never rises above the second line from the bottom. I have only had the car a couple of years, so I'm not sure what temp thermostat is in the car. Could I have a bad thermostat, or could this be a more serious issue? What kind of thermostat came stock? This is not a race car(except when I'm late for work). Should I go with a 180-190 degree thermostat? There seems to be alot of difference of opinion on that subject especially, so I'm a little confused.

 

[mercurycapri]

I sure that its one of your head gaskets leaking into the cylinders when running. Check your spark plugs and see what color they are. They should be light brown.

 

[Roland69]

check the weep hole for coolant after a run sounds like it might be a heater core

 

[s&k stangs]

Worst case scenario

I sure that its one of your head gaskets leaking into the cylinders when running. Check your spark plugs and see what color they are. They should be light brown.

OH man , don't tell me that. I dont know if the heads have ever been off the block, and right now I can't afford to have them decked to seal properly after the gaskets are replaced. What kind of damage can this do, as long as I keep fluid in it? If it has a higher temperature thermostat in it, should I put in a 160 degree thermostat to try and keep the block a little cooler? or will that just add more coolant to the mix?

 

[SeventyMach1]

First, find out what the problem is. The thermostat would not be related to you losing coolant. Does the car ever smoke at all?

I don't know about Fox's having this problem, but the 5N95 cars are notorious for getting a small pin hole in the coolant reservoir and leaking (which can be harder to spot than most people think).


On the thermostat, I think the stocker is supposed to be something like 190*. Most run like a 180* stat in the summer months. DO NOT get the 160*! It can actually cause your car to overheat!

 

[s&k stangs]

Weep Hole?

check the weep hole for coolant after a run sounds like it might be a heater core

This is a daily driver. And wouldnt a bad heater core leak out into the passenger side floor board?

 

[SeventyMach1]

I think he may be referring to the weep hole on the water pump.

 

[Roland69]

that's what the weep hole is for...to drain the leaking coolant outside of the car when a core takes a dump. It's right under the passenger side header on the firewall it's a little small tube sticking out about 1/8 of an inch.

 

[s&k stangs]

ixnay on the 160-ay

First, find out what the problem is. The thermostat would not be related to you losing coolant. Does the car ever smoke at all?

I don't know about Fox's having this problem, but the 5N95 cars are notorious for getting a small pin hole in the coolant reservoir and leaking (which can be harder to spot than most people think).


On the thermostat, I think the stocker is supposed to be something like 190*. Most run like a 180* stat in the summer months. DO NOT get the 160*! It can actually cause your car to overheat!

Ok, but is how do I go about finding out what the problem is. I'm sure i can find a leak in the resorvoir, but what's the next step? yeah it smokes, but not steadily. light blue puffs. I've been assuming its oil,its usually present under hard acceleration or a cold start.

 

[Roland69]

I think he may be referring to the weep hole on the water pump.

Na there is a little hole in the firewall just for when the core leak's so it won't leak into the floor..Sometimes the hole gets pluged up and it goes on the floor anyway.

 

[Roland69]

check at night with a blue led light the coolant will glow a bright yellow......look around the P-side firewall at the little weep hole.

 

[s&k stangs]

OH yes The weep hole, of course.

that's what the weep hole is for...to drain the leaking coolant outside of the car when a core takes a dump. It's right under the passenger side header on the firewall it's a little small tube sticking out about 1/8 of an inch.

First time i've heard of that. Thanks for the info. So obviously I havent checked that. what am I looking for, presence of moisture? Im guessing if the heater core is fine, the weep hole should be dry?

 

[SeventyMach1]

First time i've heard of that.

Haha, me too. I know there is one for the water pump ... so I thought he was talking about that. S&K, you might want to go ahead & check out the water pump area while you're there, too. And yeah, blue smoke = oil.

BTW, I noticed you're in Monroe. Check out www.xtrememustangs.com if you get a chance.

 

[Roland69]

I had my coolant light come on every 1-2 weeks or so and I could'd find where it was going and thought I had blowen a H/G. But I went out at night with a little blue light (keychain) and found that I has coolant dripping out of that weep hole. Also do you have any fog on the passenger side of the windshield at night or when it's cooler out.

 

[s&k stangs]

79MACH, What part of NC are you in?

 

[SeventyMach1]

79MACH, What part of NC are you in?

Hickory. I work in Charlotte, though. My boss man has us working in the Monroe area alot, too though .... as he's in Waxaw.

 

[Roland69]

I should also mention the weep hole is near the P-side header flange......I said it was near the header and I didn't say anything about the flange

 

[s&k stangs]

Thanks

You guys rock. As soon as I can determine the cause I'll update this thread and let you know how it works out. Thanks for all the info. This is why Mustang enthusiasts are so awesome!

 

[Roland69]

if we were ricers we would have told you it was the TB coolant tube on your SKUNK-2 throotle body

 

[Roland69]

I snaped a pic of the weep hole on my car I'll post it up later on for anyone who didn't know about that or where it is