tvanlant

iTrader: (4)

My Lq4 swapped 99 mustang has just started an overheating problem that I can't figure out. I've had the swap completed since November of 2014 and haven't had any cooling issues until now. I put the supercharger setup on in May.

I've got the radiator cap inline with the upper radiator hose, which goes to the waterpump outlet. The lower radiator hose goes to the thermostat housing.

Symptom: The cooling system can't dissipate heat. Once the temperature goes up, it can't cool it back down. It's doesn't rapidly overheat. On a 75 degree day, I can drive it for 1/2 hour before it gets to 225-230. 100 degree day it will get there in about 15 minutes. When the fan comes on, it does slow the rate of increase down, but it never actually reduces the temperature. Turning the heater on full blast will further help slow the rate of increase.

No water in the oil. No loss of water. No oil in the water.

I replaced the stock radiator with thick aluminum Steeda radiator, no change. I replaced the stock fan with 3 Spal fans (one 16", two 8"), no change. I put the stock fan back on because it pulls some serious air (it pulls air through the grille and can be felt even in front of the intercooler). I tried with and without a thermostat, no change. I flushed the radiator, heater core, block, etc rigorously with water. When I refilled the cooling system, I raised the front end of the car up, and slowly filled the water through the upper radiator hose until the water came out the water pump outlet, then reattached the upper hose. I also had the steam vent port detached to bleed any air from there. I put a new thermostat with a couple small holes to help bleed any air. I'm positive the system is properly bled. I've taken the radiator cap off while running, and the water pump is flowing well.


What else could be causing this?
This overheating problem really came from nowhere. I had been driving the car exactly how it was for months before it started having a problem. It seems to be getting worse

Project GatTagO

iTrader: (7)

Can you pinpoint the time when it started happening? Did it start when you installed the super charger and intercooler?

Andrew

Bowtiedford

iTrader: (9)

What about the water pump, since it's a variable you haven't replaced. Years ago we had a problem with a 302 and after going thru what you did we found out the the vanes in the waterpump or Impeller where just pretty much gone somehow and not moving enough water. Also as stated above, did it start when the intercooler was installed or did you reroute your belt and now the belt is slipping also?

tvanlant

iTrader: (4)

Andrew - It used to heat up to 205, the fan would kick on, and pull it down to 195 where it would shut off, then heat back to 205 and so on. In late June, I noticed it would get up to 205 and the fan would kick on and keep running, holding it at 205 or so. I assumed this was due to the warmer outside temperature. Each week seemed to get worse. Pretty soon it was running at 215 all the time. Then finally last week it got up to 225 while I was driving out to a cruise even 30 minutes away. I turned the heater on full blast and it kept it at 218-225 as long as I had the heat on. A few days ago, it started overheating to boiling point around 230-235, even with heater on full blast.
Supercharger was installed in May, and it ran 205 for several weeks before all this started.

Bowtieford - The waterpump was purchased new when I did the swap last november. I haven't pulled it off yet, but water is moving quickly through the upper radiator hose when I had the thermostat out. Think the pump could still have an issue?

Bowtiedford

iTrader: (9)

Ok not sure, how about one of the tensioners not applying enough pressure on the belt causing it to slip?

DavidBoren

Is the radiator at least as big as a stock six liter radiator? Even an oversized 302 radiator may not be adequate for your application.

When you installed the blower, did the location of the air filter change?

If it's breathing hot engine bay air, that may contribute.

Does the blower use engine oil? If so, the blower might be heating your oil faster than the water can extract the heat. Maybe add an oil cooler and see if that helps.

Do you have heat extraction vents in your hood? If no, why not? You should.

Check your belt(s), and ensure that you have proper tension on the water pump pulley.

Have you wrapped, or coated, your exhaust in the engine bay?

toxic99

What kind of temp gauge? electric or mechanical? where are u pulling your temps from?

jimmyg

U need a 4 way mixer valve like everco 5930 . the thermostat needs the flow to work properly. I just went thru this. It didn't over heat in the winter because you were running heat. I put a 160 thermostat, 4 way mixer valve and a set of derale 4000 cfm fans. Even with Ac on in 100degree weather in traffic my car never goes over 180. I would look into a H O fan / shroud set up

tvanlant

iTrader: (4)

DavidBoren - The radiator is very large, probably 3" thick, aftermarket aluminum. Larger than the one in my 6.0 truck.

Belts aren't slipping. The supercharger has it's own dedicated belt, so it doesn't affect the other accessories.

The supercharger system is intercooled, so intake air temps are ambient at idle and cruising.

Blower is self contained oiling.

Yes, the headers are wrapped.

Toxic99 - The temp gauge is a stock 6.0 electric gauge, placed in the cylinder head port on the rear of the passenger head.

jimmyg - what does that valve do? Water is still circulated through the heater core even with the heat off.

jimmyg

Most people use a vaccum operated mixer valve that will stop flow to heater core when heat is off .ls motors require one that cuts off flow to core but loops it back to water pump . For proper thermostat operation. This was the problem with my car, that and not enough air flow. I'm not sure how mustangs are set up though . I do know that if the temp sender is in the pass side head it will read hotter than drivers side. You could also try putting it in drivers side head that's where gm put it

lsxRanger94

Try putting washers and a longer bolt on hood hinge to raise the back of the hood. See if this helps. If so, look for an airflow issue. Possibly a plugged rad with bugs or other airflow issue through the engine compartment.

Old Geezer

iTrader: (3)

What about the tune? Lean/fat?
Data logs?
Leak down test for fried head gasket[s]?

ijimmy

My first guess also , ive seen them go bad

smitty2919

Not quite. How many people do you see having a SC motor with no heat extractor vents....plenty. Don't go cutting up your hood. Adding hood vents will not fix this issue. The temp rise is too much to be solved by simple hood vents.

Have you blown out the AC condenser of any dirt? If it is clogged it could be blocking air flow through the radiator, plus having intercooler in front won't help.

rg913

there is no air conditioning on it any longer, all the parts are brand new as of this year there is no dirt or bugs in the radiator or intercooler. It gets washed.

blueracer15

iTrader: (2)

boost leak test should give you the best answers

DavidBoren

As for the heat extraction vents... They work, for one. And I happen to like the way they look. So it's easy for me to bring it up.

I would look into that mimixer valve. And try putting the temp probe into the other head. Maybe even throw in a lower temperature thermostat.

smitty2919

I never said heat extractor vents don't work (assuming you place them in the correct spot). But at the same time, they will not keep a motor cool that was once overheating on a street car application. There is a bigger issue here.

I don't see why a setup like this should be running at 220* if you are not beating on it or getting into boost. It should run like a normal car cruising down the highway or back roads.

Double check the temp sensor in the head. I would get a better aftermarket one IMO. They have been known to be problematic. Worth looking into.

tvanlant

iTrader: (4)

Old Geezer - tuning is done with a Holley Dominator, so A/Fs are spot on. I've got it set to 14.0 cruising, 10.8 WOT, and it's on E85.

others- how would the heater bypass help? Water is flowing fine through the heater core, which is actually helping reduce the heat when I need to turn it on.

jimmyg

So what happens to flow when you shut heat off? Your hvac system would be terribly inefficient of hot coolant was flowing thru heater core with Ac on. I'm not sure about 99 up stangs but I do know plenty of fords use a vaccum operated mixer valve