Overheating?

[Gary13]

Hi,
The hot weather has returned to Texas and with it higher than normal engine temperatures, at least when reading the water temp gauge. The car has always indicated water temps on the stock gauge between the "O" and "R" during the summer months. For the past week, the gauge has been reading between "A" and "L" even on constant drives where the car is in fifth gear at around 60mph with outside temps around 90F. It has been three years since the radiator fluid was changed (only 2000 miles) so I had the radiator flushed and refilled with new antifreeze. There was no indication of trash or buildup in the system. I also had the radiator cap, thermostat housing and thermostat replaced (192F Motorcraft) at the same time. The shop said the hoses appeared to still be in good shape (replaced with the radiator five years ago, 4000 miles).

Now the gauge reads at the "L" mark or just to the right of it. It does not appear that the hoses are collapsing (springs are installed) but there is no overflow going into the auxiliary tank once the engine is hot or showing to be near an overheat condition according to the gauge. I replaced the hose going from the cap to the tank as it was sucking close. Still no changes so I replaced the temp sensor gauge with a new replacement and no changes on the readings once the car warms up. I even set the aftermarket fan to operate 100% of the time and no change to the gauge readings after driving the car for about 15 minutes.

At this point without taking the car back to the shop for an expensive diagnosis, does anyone here have any ideas what could be causing this issue? I would assume at this point I am down to replacing the radiator or water pump next.

Any assistance would be greatly appreciated.

[Mike S]

Take your radiator cap to Autozone and have them test it with their rental tester. If it is not holding 16 psi, replace as needed.

[k98dave]

Ditto on the cap test. Also do you have access to an IR temp sensor? Need to get readings from radiator, upper & lower hoses and T-stat housing. Also have you tried running the heater to see if the temp gauge shows any change?

"Help Wanted - 1985.5 SVO needs a full resto..."

What resto work are you going to do? I'm just about done with an 84.

[stott]

stock fan?

sure your fan is running?

[Gary13]

stock fan?

sure your fan is running?

No, an aftermarket fan and yes it is running throughout the drive and when idling. I have the ability to set the fan speed also, turned it up to 100% at idle just to make sure. I already replaced the cap with a new Motorcraft replacement. Tried two more caps from other manufacturers and still the same issue. Had the Motorcraft cap tested and it was fine. I ran the heater (it was not comfortable, ;) ) and no differences. Next up is the IR temp sensor test as suggested above. Thanks for all the suggestions so far.

[Chuck]

My 86 had the same temperature habits as yours. I went to pull the fan speed switch from the lower intake manifold and it broke off. I pulled the intake manifold to have the switch removed and the lower water passage was completely blocked by junk. After a good sandblast and cleaning of the lower intake, I had a working fan and the temperature again read in the O and R range of Normal. This is even in the summer in Phoenix.

[Gary13]

"Help Wanted - 1985.5 SVO needs a full resto..."

What resto work are you going to do? I'm just about done with an 84.

I have completed a ground up replacement program on the car with everything from the suspension bushings to dew wipes to mirror lamps being replaced for the most part. The engine, rear end, and transmission have all been rebuilt along with most of the chassis components being replaced. I even had the wheels refurbished. About all that is left is the paint (right now it is a 90% good), carpet and few details like a decent stereo unit and some under-hood cleansing. I have put like 4000 miles on the car since 2005. Unfortunately (hope this does not get me banned here as it did elsewhere) I got hoodwinked when I purchased the car from a supposed SVO enthusiast from the site that will not be mentioned. :p The car looked perfect, acted well on the test drive from the airport and was guaranteed to be in great condition but broke down twice on the drive home (St. Louis to Dallas) and afterwards it turned out to be all smoke and mirrors. I could go on and on about what the local shop and SVO enthusiast discovered but in the end I screwed up trusting someone with a name in the community instead of having a mechanic look at it in detail. First and last time I ever buy a vehicle in that manner.

[Gary13]

Fixed (almost) - Thanks to the IR sensor test we determined there was blockage in the system. We did another system flush and sure enough a few tidbits came out and the temps almost fell back to the previous readings (sits between the R and M after 45 minutes of mixed driving). At this point the car can be driven in hot weather if needed and I will replace the hoses (discovered a few spider cracks on the lower) when the manifolds are pulled for replacement. I appreciate the assistance as two of the shops just wanted to replace the water pump and radiator after a "cooling check".

[k98dave]

Glad you made some progress. Sometimes its just better to replace the radiator to get back to 100% Thats what I wound up doing on mine. Now the temp gauge just gets to the "N" I don"t have my AC system up yet so I'm sure that will add some temp. See my post about Restoration List. http://www.svocop.com/forum/showthread.php?1775-Restoration-Repair-List


Since your in Dallas we should meet at one of the local car shows. Also There is a shop in Alvarado right off I35 that is the only place I will let work on my cars. Owner is Keith and shop phone is 817 226 6111. Very reasonable rates and knows mustangs 64-93 inside & out

[alanmassengale]

Is that shop in Alvarado still there? Not seeing it with a recent search.

[Under Pressure]

Yes it's still there, they have a big sale on everything.