coolant temps

[suv7734]

I bought the truck in january of 08. It was a mess to say the least. after rewiring the back half to get tail lights, putting in a new vacuum pump, and replacing the fuel filter I drove it 120 miles home. Over the next two weeks I stripped and cleaned the interior (literally a 5 gallon bucket full of sand, dirt and dog hair ), rattle canned it black and started driving it daily.

I drove it till april and noticed it liked to get hot (this was in florida where the asphalt gets to 140+) pulled the cap and found rusty liquid. Bought flush, cap and hoses. Flushed till clear, filled with new coolant and dca4 after installing the cap and hoses. That lasted till may when the waterpump started leaking. Replaced the lower hose again (had a pinhole in it from the parts store hang up loop) the water pump and the thermostat.

about a week after this I swapped in the zf5 and installed the hypermax kit, turned the pump up two flats and put the first set of stacks on it.

Got hot once coming across montana on the way out here. flushed the cooling system and refilled again, replaced the cap and made it here.

I have been working at a dealership so I flushed it a couple times there and the time before last I installed a coolant filter. The coolant stays the correct color but I think the system has deposits in it from the PO (S) before me.

I need to pressure test it and I guess I need a new radiator.

from what I understand these things have such a big cooling system that is so efficient they rarely get even kinda hot. I think mine is pushing the limit and I hope I havent already cracked the heads.

punk

Two things come to mind, they may have been addressed and I missed it but...

I don't see anywhere that you have changed the thermostat. If someone put in an incorrect aftermarket one, that can cause a problem.
The second item is if the fan clutch has been tested or not.
For me if the engine is seeing 230+ in any area, regardless of location, it is getting hot and something needs to be addressed.
Just some thoughts...

Good thread BTW!

 

[punkmechanic]

first I really like that sig suv. Second I replaced the theromostat when I did the waterpump (sorry I think I forgot to put that in). I can hear my fan coming on (its a sound hard to miss for any that are wondering). Im really at a loss on this one. It only gets that hot when pulling hills so it could have been this way all along (no hills in florida). Im thinking of pulling the radiator and getting a new one or haveing this one cleaned and put it back in (thats about 150 with a two day turn around, not an option at this point.

punk

 

[Greenie]

An IR no contact temperature reader can really help diagnose cooling problems; check the block temperature, the thermostat housing, upper radiator and lower hose.
My radiator never leaked but it did make the engine run hot as the foil between the cores rotted away. A new radiator made all the difference.

 

[dakotajeep]

Greenie,
When was your engine overheating with your old radiator. All the time, under load or at idle....give us more info. What type of radiator did you get?

Thad

 

[Greenie]

My 1993 F-250 started to run hot only when towing in 2005. It set the dashboard warning lite and pegged the gage. We were a long way from home so we had to run the heater on high with the windows open and stay off the accelerator. It boiled over on a short trip between work and home - again towing a 3 ton travel trailer.
I changed the thermostat, replaced the fan clutch and the radiator all about the same time so it's conjecture as to what fixed it. I'm pretty sure it was the reduced surface area on the radiator that caused the overheat.
The thermostat appeared to be OK but the rubber seal got pulled into the path of coolant, impeding the flow a little.
The radiator however had lost much of the thin foil webbing due to salt from our winter roads. I called around and ordered what I was told was a Canadian radiator. When I picked it up it was obviously from China. I used it anyway, 4 rows and it fit good. I can't remember the brand and I think it cost $350.
Now I can tow the same trailer in 95 degree weather in the mountains in Mexico and run about 220 - maxing out at 230. I can pretty much stay around 70 mph as long as there's no strong headwind.
I added a water temperature gage with the send in the top of the water pump - where the square headed plug is located.

 

[punkmechanic]

I have an ir thermometer and will do some investigateing this weekend while pulling the grades headed to bend. Im swapping radiators while Im down there to see if that makes any difference or not. Im kinda frustrated with the whole mess. I love this damn truck and really dont want to destroy a motor over something as simple as heat. Im afraid I may have done something already but wont know till get a second vehicle and get a chance to pull the heads (want to update the gaskets, clean things a bit, and put in studs)

punk

 

[69dieselfreak]

have you thought of blowing some compressed air through the rad to see if the fins are pluged up with mud dirt etc.

 

[typ4]

Greenie , that port in the water pump is cold water, not hot flow out of the heads.

 

[Greenie]

But it corresponds with the stock gage - the top of the water pump is a sample of coolant temperature before it passes through the radiator.

 

[OLDBULL8]

it just sounds like you need a good flush and if that doesnt work then you might have to have you radiator rotted out

You cannot (rotted) ROD out these radiators, the tubes have slight zig zag's in them. They have to be boiled out at a radiator shop. If they rod them out they can punch hole's in the tubes. If the tubes are plugged and can't be boiled out, then it's a new radiator. Ask me how I know.

I have a mechanical gauge by #8 cyl. (90 IDI) found that is the hottest spot, checked with a laser thermometer. As long as I don't get over 240 towing I feel I'm real safe. That head location seems to be the place they crack 1st.

 

[typ4]

NExt time you have the water pump off have a look. The impeller picks up water from the bottom of the rad, then pushes it thru the block and rear of the heads then back into the crossover in the front of the block to the t-stat. I have carefully studied this to try and sort out my heating problem.

 

[CDX825]

Seen there was some all aluminum radiators on ebay for our truck for less than $250.

 

[k_williams1982]

I have an ir thermometer and will do some investigateing this weekend while pulling the grades headed to bend. Im swapping radiators while Im down there to see if that makes any difference or not. Im kinda frustrated with the whole mess. I love this damn truck and really dont want to destroy a motor over something as simple as heat. Im afraid I may have done something already but wont know till get a second vehicle and get a chance to pull the heads (want to update the gaskets, clean things a bit, and put in studs)

punk

Be sure to call before you head this way. We got more snow tonight and I had a voicemail this evening from a temp agency in town wondering if I;m available for work. I'll know more tomorrow when I can call them back.

 

[Greenie]

NExt time you have the water pump off have a look. The impeller picks up water from the bottom of the rad, then pushes it thru the block and rear of the heads then back into the crossover in the front of the block to the t-stat. I have carefully studied this to try and sort out my heating problem.

I'll have a look... but if memory serves I have a 190-200 reading on the gage consistently when it's cold outside and the bottom of the radiator is only warm. We talking about a 7.3 IDI?

 

[f-two-fiddy]

With the crap You flushed out of the radiator, I'd jsut replace it. I'd bet the radiator is all scaled inside.

We have a 2mile hill here that I pull 8-10 times a week. When temps are 80+ I can watch the factory gauge climb until I hear the fan clutch engage. Then it cools right back down. 12 lbs of boost really gets the coolant hot.

Another thing I've always wondered about is the changes in the heads. From 6.9 to 7.3 I recall there is some differences. Gasket changes to seal off coolant ports? Would it be prudent to cut the head gaskets to include the blocked off ports?