Cooling system questions

[strok-n]

Alright guys so I am trying to figure out some issues I seem to be having with my cooling system. Truck was running hotter than normal. It was at 215-220 at cruising speed. Checked coolant it was full, so I check the top hose on the radiator and it was not pressurized. So I figured my thermostat went out. Replaced the thermostat after doing a full coolant flush, and now I am still having the same issue. Any thoughts to what it could be

 

[Northwoods2002]

Where did you get the tstat from? IIRC there's a couple different 'styles' and if you don't get the right style it will cause those symptoms...

 

[NC714]

If it is not pressurized but you have no evidence of external leaks, I would try a new degas bottle cap. Where are you reading the Engine Coolant Temperature from?

 

[IHPowerstroke7.3]

X2 on trying a new cap, wouldn't hurt to pressure test the cooling system if you can get your hands on a pressure tester.

 

[strok-n]

Ok the thermostat is one from Terminator, and I will swing by and grab a new cap today to see if that is the problem. I have a scangauge so that is where I am monitoring the temps

 

[DEEZUZ]

+1 for confirming tstat. There is a short and a long one

 

[Ron's Power Stroke]

if this truck has an auto trans the PCM does not read coolant temp..it uses oil temp and your 215 sounds about right..the stock coolant temp sensor only sends reading to the dash gauge,,you need an after market gauge with a sensor if you want real coolant readings..

 

[weekendwarriorfsw32]

With terminator's thermostat I see 180 on the nose all day long via my auto meter coolant gauge. Make sure your fan clutch is not broken.

 

[strok-n]

if this truck has an auto trans the PCM does not read coolant temp..it uses oil temp and your 215 sounds about right..the stock coolant temp sensor only sends reading to the dash gauge,,you need an after market gauge with a sensor if you want real coolant readings..

It has an auto, but I can watch oil temp and coolant temp and they are not the same, they usually differ about 5-10 degrees. So I don't know but it doesn't seem to be reading the oil temp

 

[strok-n]

With terminator's thermostat I see 180 on the nose all day long via my auto meter coolant gauge. Make sure your fan clutch is not broken.

The problem is the thermostat is not opening. The fan clutch should not have anything to do with that. I am willing to check everything just thinking its more of an issue with the thermostat.

 

[Arisley]

If the thermostat wasn't opening, it would get a lot hotter than 215º. It would overheat, and buy a lot. I will agree that the thermostat would be the first place I would check. At 215º you should also hear the fan clutch locking up. Sounds like a jet taking off under your hood. Also, how many miles on your water pump?

 

[weekendwarriorfsw32]

Incorrect. I had a 7.3 a couple moths back over heating, tuned out the fan clutch was so far gone it was just free spinning and it was causing a restriction. The guy replaced everything before that ( Rad, thermostat, oil cooler, water pump )

The problem is the thermostat is not opening. The fan clutch should not have anything to do with that. I am willing to check everything just thinking its more of an issue with the thermostat.

 

[Arisley]

OK, so if it gets hot and you never hear it come on, that would be a clue that it is bad.

There is no mistaking when it comes on.

I live in TX. The only time mine comes unless it has a load on it, is summertime after about twenty to thirty miles at freeway speeds. It will come on every five or ten minutes for about a mile or so. Now, if he is seeing 215º and not hearing the fan come on, I agree that it may be bad. However, it is not the first thing I would suspect. A thermostat is simple to check, throw it in a pot of water and put it on the stove. If the water boils before the thermostat open, you have a bad thermostat. with the thermostat removed, engine cold, start the motor and see if the pump is moving water, a lot of water. Also the reason I asked about the water pump. They are usually the part that goes out quickest. You can check the fan clutch, the procedure for it is a PITA, but there is a procedure to check it. They do occasionally fail. If I was throwing parts at a problem instead of diagnosing it and fixing it right the first time. I would start with the thermostat, than the water pump, than the fan clutch., than radiator.

 

[strok-n]

Ok so I agree the fan clutch could be bad, but that doesn't explain why the truck is getting to 215 at idle. The thermostat should be opening at 180. I will pull the thermostat this weekend and test it. The water pump only has 3k on it. Hopefully it didn't go out that quick.

 

[Arisley]

True. Yes, test the thermostat. Make sure you didn't put it in upside down also.

 

[strok-n]

Ok so I just replaced the reservoir cap, and the system seems to be pressurizing once it hits 180, but the temp is still going over 180. In park if I rev the truck up the temps will climb steady. I can go from 190-200 in about 30 seconds. Any clue on this one.

 

[crcrawford87]

Have you checked the radiator and condenser and charge air cooler for a restriction from dirt and road grime? If this is too plugged up the fan clutch will never work properly as it's not getting airflow across the thermostatic spring in the front of it. A brand new clutch won't work for sh*t if it's not getting airflow across it. Did you run the engine up to temp with the cap off the degas bottle to purge out all the air in the system? I also run the heater on low while I'm doing this to ensure there is no air in the system, if you don't vacuum fill the system I can guarantee there is air in there.

 

[crcrawford87]

Using compressed air is best for this and if it's real dirty you can spray it down with vinegar first to break the gunk down. If you remove the bumper and grille and header panel you will have good access to clean everything out. I wash mine out at the car wash every time but I still spent 1-2 hrs with a blow gun the other day and I was surprised how much stuff came out, the cores were packed with dirt and sh*t.

 

[strok-n]

Using compressed air is best for this and if it's real dirty you can spray it down with vinegar first to break the gunk down. If you remove the bumper and grille and header panel you will have good access to clean everything out. I wash mine out at the car wash every time but I still spent 1-2 hrs with a blow gun the other day and I was surprised how much stuff came out, the cores were packed with dirt and sh*t.

I will give this a try over the weekend. Thanks

 

[NC714]

if this truck has an auto trans the PCM does not read coolant temp..it uses oil temp and your 215 sounds about right..the stock coolant temp sensor only sends reading to the dash gauge,,you need an after market gauge with a sensor if you want real coolant readings..

Not sure if you seen this post. If you reading the coolant temp through the OBD2 port on a truck with an AUTO pcm it will not be accurate. You might be getting worried over nothing.