Cooling issues... car won't heat up, but Tstat and Rad are new.

[TomCat]

Well my car is at it again... this time it won't heat up properly. I gets up to about 140 on the gauge and no further. Within the last 2 month, the entire cooling system (minus the heater core) has been replaced. New WP, radiator hoses, radiator itself, cap, Tstat... I don't really get what's going on. The upper radiator hose is really hot after driving, but the lower one is ice cold... and when runnig neither of them are hard to squish, they're really soft. Any insight?? I can see how a Tstat stuck open would cause it not to heat up, but it wouldn't really explain the hoses?? ANY input is welcome!

Thanks,
Brandon

 

[HISSIN50]

Brandon, is this per the stock guage? If not, where is the sender mounted for your gauge?

This time of year, the cooling system should not be too burdened and I have to say that it does not sound terribly off to lil' old me. The water in the radiator gets pretty chilled while sitting there (it can take a bit for the motor to heat up the coolant in it) so when that stat opens, the cold coolant from the radiator takes care of business.

My two cents.
Good luck.

 

[TomCat]

Yah it's the stock gauge. Hmm... I checked it all after about 20 minutes of driving, so I thought the engine would have had plenty of time to warm it up. It is 38* outside right now though...
Thanks, I'm off to check it out again...

 

[88Stangboy]

Well stock gauges are little more than idiot lights anyhow. If its that cold outside than your engine isn't going to get up to 180 anyhow. Mine usually gets up to about 175ish when its about 50 outside and thats with an autometer water temp gauge, my engine usually runs a little hotter anyhow, i need a bigger radiator. I wouldn't worry to much about it, its better than over heating right? I would love to have the burdon of running to cool, at least in the summer....BTW whats the specs on that cam?

 

[HISSIN50]

Now knowing it is per the stock guage, though they all differ, I can tell you that in even mild temps here (say 50*F ambient), the stocker will read at 135* F, even though my mechanical guage reads 170*F. The stockers can be off by a good little bit.

If one is careful, you can start with a cold motor. Put a turkey thermometer in the radiator neck (BE VERY CAREFUL OF ANY HOT COOLANT WHICH MIGHT BURP OUT OF THE RADIATOR, ETC). Watch the turkey gauge vs your gauge and you can get an idea of how far off they are. Of course, you are measuring the temps in two different locations, but they should not be that far off. DONT use the turkey thermometer for food of any sort afterwards (turkey thermos at wally mart are like a buck).

Good luck.

 

[fox_bodies_rule]

You said everything was new but you didn't mention the temperature guage sending unit. My guage was reading about 140 but felt hot enough that you didn't want to leave your hand on the radiator. Changed the sending unit, guage starting reading about 220 to 240 and guess what, I did have a heating problem! fixed that (long story) and now it reads right in the middle of the dial which is about 195, what the stat is rated at. If you decide to change the sending unit, make sure you change the one to the guage, not the one that sends a signal to the ECM. Hope this helps. Cooling systems and Mustangs, Argh!

 

[TomCat]

That's true, I never changed out the sending unit... Maybe I'll just drive it a bit and see how it goes... it's not like I ran into any driving issues, just the gauge got me a little worked up. Thanks for that idea about the thermo, I'll probably grab one just to make sure I'm running in the right temp. range.
Oh and the cam, here's what the guy who sold me the car said: Dur. 230/230 @ .050 Lift. .512/.512 ... I'm not sure on the comp cam number, but I think he said it's comparable to a Ford F cam. Don't know whether or not I like it... stock 5.0s seem to have much more low end than mine. I'll have to call him up and get the number so I can look it up... =( I don't know much about cams. However, I do know that when I do the cyl. heads this spring or summer, I'll be getting a new cam to go with them.

Thanks!

 

[jadedinpa]

how hot is the air coming out of the vents?

 

[TomCat]

Mildly warm

 

[jadedinpa]

same here. my gauge reads around 160 i think (haven't driven it in a week or so).

 

[srothfuss]

How long does it take to get "mildly" warm?

My car @ idle takes about 1/2 hour before the thermostat opens at 195. That is when my heater works the best.

 

[PRO50SC]

What size radiator did you put in it? What about your fan, what kind? Stock or electric? What temp t-stat did you put in?

 

[TomCat]

Ok I'm not sure on the time it takes, but after 20 min. of driving in the city, it was still mildly warm. My new radiator is about 50% thicker than the stock one, but otherwise the same dimensions. I run a flexfan and I put a 180* Tstat in there.

 

[PRO50SC]

Get rid of the flex fan, that a coupled with the fact that you're now using a thicker radiator. You may have to go to a 195 stat for the winter months.

I just put an aluminum 2 core in mine and it takes a while now to get warm. But it does reach 180.

The flex fan is killing you.

 

[TomCat]

Alright... do you think switching back to the stock clutched one would be sufficient?

 

[HISSIN50]

The stock clutched fan is a thermal clutch and might work a little better in the cold temps. Or you can do the shadetree method (Bernie, cover your eyes. ) and partially (but securely) cover the radiator with a piece of cardboard, etc.

Good luck.

 

[mustangmarks]

Alright... do you think switching back to the stock clutched one would be sufficient?

Hell no!! keep the electric. Now I was told this but I guess to see if your sending unit works you take it off and put it in hot water and see if the gauge reads? Tried it with mine and found it was the sending unit. Now the stock gauge is damm close. Good luck

 

[srothfuss]

He's running a FlexFan... not the Flexilite e-fan. I thought that too when I first read it. The mechanical fan is constantly pulling cold air across the radiator and onto the engine which is probably what is causing you your long warm up times.

A switch to an electric fan with a DSS controller might be a good idea here also. Since the e-fan won't run all the time, it'll allow your radiator / engine to warm up a little faster.

 

[PRO50SC]

The stock clutched fan is a thermal clutch and might work a little better in the cold temps. Or you can do the shadetree method (Bernie, cover your eyes. ) and partially (but securely) cover the radiator with a piece of cardboard, etc.

Good luck.

LOL!!! I had an old Bronco that I used to have to do that to. No biggie!!

 

[HISSIN50]

The t-stat is what regulates the engine temps. So having a mech fan cooling the air a little extra while at low or no speeds does not appreciably matter. Said another way, while on the highway, the coolant in the radiator becomes very cold. Once the coolant in the motor heats enough to open the t-stat, that super cool coolant enters the motor and circulates until the stat closes. Then the coolant is heated in the closed side of the motor.

So the mech fan might cool the radiator's coolant a bit more while stationary or at low speeds, but it really is of no significant consequence. A clutch fan should not lock up when the ambient temps are cooler anyhow (ergo underhood temps are lower). So a clutched fan should be a happy medium between the direct coupling of a flex fan, and an e-fan.

Just MHO.