'94 5.0L overheating

[Stangman]

This is going to sound dumb... but my '94 has been overheating for a year. Yeah I know, but I dont drive it that much.

I put a water pump and tensioner on it 164,000 miles (approx. 2.5-3 years ago) and it was great until last year when it started getting VERY hot, almost to the end of the word NORMAL on the gauge. And it was one of those things where it ran cool one day, and the next day I happen to look down at the gauge and it is extremely hot. well, I had the radiator flushed and it had a LOT of build up in the engine/radiator. I flushed it at a shop and had it replaced with a mix of coolant and distilled water.

that made it okay but now it is getting very hot again. I have to cook myself with the heater on full blast to keep the car cool.

I love driving this thing but fear that it is going to have a nuclear meltdown on the side of the road somewhere and dont want that to happen, especially at the track! :eek:

So now that makes my water pump approx. 60k old... what is the life expectancy on a aluminum water pump nowadays? I mean, my radiator is getting flow, so it has to be working...

Also, how likely is it that my heads or my radiator is still clogged? Or I have a cracked head gasket?

I think first off I'll do a coolant flush again and see how bad it is.

Anyone else have any ideas what to look for?

[RACEME]

This may be dumb, but you have checked the elect fan correct? FWIW my 95 ran hot anytime I was agressive with it. The stock cooling system is kinda weak on those years. If you have underdrive pulleys on it you may need to make changes to get the water pump spinning faster again.

[Stangman]

This may be dumb, but you have checked the elect fan correct? FWIW my 95 ran hot anytime I was agressive with it. The stock cooling system is kinda weak on those years. If you have underdrive pulleys on it you may need to make changes to get the water pump spinning faster again.

I can hear my fan kick on so I do know that it works... I don't have underdrive pullies either. I thought that maybe the fan motor was getting weak, but if that was the case I would probably get excessive draw on the charging system.

Before I didnt have any problem with it, I could beat on it as hard as I wanted all day long and the needle wouldnt move.

[todd86]

Change the head gaskets

[Clean91lx]

Are you sure the t-stat is not stuck "partially"? I have seen that happen..not necessarliy on a mustangs

[85_SS_302_Coupe]

Have you ever had to put head gaskets on it? If so are you sure you put them on right? That's a very common mistake...causes over heating if you don't follow the "front" directions on the gaskets.

[Stangman]

Never cracked the motor open on it. Most I've replaced is upper intake gasket, water pump, and rear main seal. 227K now.

I had a coolant flush done on it a couple months ago, seemed to help but not fix it. I think it just needs flushed 2 or 3 times in a row, but nobody wants to do it with the machine without charging me 100 effin dollars each damn time... seriously isnt even worth the money but they got ya by the balls.

[zlou363lx]

just give it to me. i'll take care of it from there ;) lol

i kid, i kid.

[Stangman]

lol

Yeah it's sleepin for the winter right now though, so it doesnt bother me that it gets a little warm, I dont drive it enough now to make it. took it around the block the other day... wow my power steering is trash.

One of these days if the motor lets go, I'll throw some heads and intake on it... might get it into the 14's hahaha

[85_SS_302_Coupe]

Are you positive you used the right gasket when you replaced the water pump? I think there's one that can partially block one of the water holes or something alone those lines.

[Orodi]

my bet is a sticking thermostat.

[Stangman]

Are you positive you used the right gasket when you replaced the water pump? I think there's one that can partially block one of the water holes or something alone those lines.

SN95's only use 1 gasket, unlike 2 for a fox, and I replaced that back when it at 165K on it... so that rules a gasket out


my bet is a sticking thermostat.

replaced it. With a fail-safe unit

[RACEME]

There are only two things that I can think of now that could cause this. Something is slowing the coolant flow. More than likely the radiator. The other thing is if the coolant sensor is wrong.

[Stangman]

There are only two things that I can think of now that could cause this. Something is slowing the coolant flow. More than likely the radiator. The other thing is if the coolant sensor is wrong.

I think you're right. I do think that it is the rad. Sometime in the spring I'm gonna yank it out and flush it myself. Along with probably putting a power steering pump and rack on it!

[INSANEBA]

You can get replacement rads new in the boc CHEAP from fleabay. Just toss another one in and see what happens, I think you can get em shipped for around $50

[Stangman]

crappy part is... radiator isnt but 4 years old. Had it replaced when I got the car (plastic tanks were leaking)

We'll see what tax time brings :D

[pegasus]

does it over heat when your driving it at speed? or when its ilding?

[Stangman]

does it over heat when your driving it at speed? or when its ilding?

Mostly at speed, or if im beating on it. When I took it to the track at the end of last year I had to crank on the heat once I passed the stripe!

[Orodi]

What exatly are the mods on the car? I'm running a 331 afr heads and aftermarket waterpump through a stock radiator with no problems. Could you maybe running lean? That would explain the heat problem if there's no leaks or anything with the cooling system

[85_SS_302_Coupe]

I can't see a 4 year old rad being clogged up so fast. I'm running a stock '89 radiator with a 347 and a stock replacement water pump and my has never overheated. What you need to do is get a real temp gauge and hook it up and see what temp the fan actually kicks on.

[Stangman]

What exatly are the mods on the car? I'm running a 331 afr heads and aftermarket waterpump through a stock radiator with no problems. Could you maybe running lean? That would explain the heat problem if there's no leaks or anything with the cooling system

Physically bone stock. It has 3.73's, control arms, shifter, CAI, exhaust (stock headers) and It's not running lean, its actually running stupid rich since my MAF isnt calibrated for 24# injectors, but it was running hot before I did that swap.

I did have an injector go bad on me a few months before I stopped driving it though... could that have caused a problem? It ran on 7 cylinders sometimes, but not all the time


I can't see a 4 year old rad being clogged up so fast. I'm running a stock '89 radiator with a 347 and a stock replacement water pump and my has never overheated. What you need to do is get a real temp gauge and hook it up and see what temp the fan actually kicks on.

Me either... thats what gets me... I think when the shop did a flush on it once, they used tap water... the minerals have formed buildup now...

[85_SS_302_Coupe]

^^^ uses tapwater :o

[Stangman]

Distilled water or 50/50 is what should go in it I do believe

[windsor86]

leak down test? air in system? t stat. any codes? lots to be tested here it could be found in a short afternoon with the right tools and knowledge

[todd86]

Change the head gaskets

It has a deteriated head gasket. How many times have u got it hot? 99.9% sure its not the tap water. You need to check for CO in the coolant, do a leakdown test. Does it push coolant into the overflow?

[todd86]

leak down test? air in system? t stat. any codes? lots to be tested here it could be found in a short afternoon with the right tools and knowledge

Have a tech checkk it out instead of wasting all your time and money!

[Stangman]

leak down test? air in system? t stat. any codes? lots to be tested here it could be found in a short afternoon with the right tools and knowledge

T-stat changed, read thread...


It has a deteriated head gasket. How many times have u got it hot? 99.9% sure its not the tap water. You need to check for CO in the coolant, do a leakdown test. Does it push coolant into the overflow?

It never pegs the gauge, but gets warmer than I know it should. As far as pushing coolant into the over flow, I dont believe so, but I've never looked


Have a tech checkk it out instead of wasting all your time and money!

Pretty much... just need time. lol

[Camaro86SHOCKER]

I can't see a 4 year old rad being clogged up so fast. I'm running a stock '89 radiator with a 347 and a stock replacement water pump and my has never overheated. What you need to do is get a real temp gauge and hook it up and see what temp the fan actually kicks on.

Agreed, before you go ripping into replacing a bunch of expensive shit, put a real mechanical temperature gauge on it and install it all nice on the car lol.
In my experience the factory gauges mean nothing, theres alot that could be going wrong that has nothing to do with your cooling system.

Could be a air pocket where the gauge sensor is causing it to read hot, could be a worn out temperature sensor etc, If after you put a real gauge in it and it still reads hot i would look at the water pump. Even though it has been replaced, 60k is not unheard of for a pump to fail. Even if the pump is moving water it may not be moving the volume of water that it needs to, perhaps the propeller fins inside got bent or chipped or weakened by debris from the cooling system.