Engine Running Cold

[Old Goat]

Pick up one of these Infrared Lazer temp gizmos.
Point it around he engine to see what the actual temp is.

12:1 Infrared Laser Thermometer

Amazing deals on this 12:1 Infrared Laser Thermometer at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

I agree on Card Board in front of the radiator. Does help with getting some warmth out of the Heater Core.



Goat

 

[Clb]

Don't open a hot radiator unless you have a lever vent cap.
And then still cover it with a towel so if it steams/spits up you are covered.

From a cold eng...
Open the cap observe coolant level, fire it up and see how much the bypass is moving coolant, then either just let it idle till hot no cap, or set the cap on and turn it just to the first "catch" notch so it wont fall off but not seal up.
This way you can high idle it to hasten the warning.
Realize that when the stat opens it may puke a little.
Turn on the heater and wait for toasty warmth then you should be warmed up.
Go watch the flow again.

 

[Clb]

Goat hit on something...
Temp gun.

Ok so old codger statement...

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Do fill in the truck stats in your sigline, so we know what we are working with..

Do you have a pyro?

Lets do some crowdsourcing

My 93 idit hot, (fully warmed up) will idle at +-190 degrees summer, hotter days maybe 210 .
The egt's are 250-275 deg. once stabilized.

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[mexicanjoe]

Your fan clutch could be frozen up and causing the engine to run cooler. The problem I have with my truck, however in the heat of the Texas heat it never gets above 10 degrees pulling a fully loaded 23' livestock trailer ( with the air conditioner on, i might add.)..... Makes a heck of a noise driving around town, but no overheating issues.

 

[MJGenay]

Pick up one of these Infrared Lazer temp gizmos.
Point it around he engine to see what the actual temp is.

12:1 Infrared Laser Thermometer

Amazing deals on this 12:1 Infrared Laser Thermometer at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

I agree on Card Board in front of the radiator. Does help with getting some warmth out of the Heater Core.



Goat

Will order one, nearest harbor freight is like 2 hours away. I have some semi cheap gauges on order for coolant temp and oil pressure, I will install those once they get here. Also have another thermostat coming in tomorrow, however, I'll probably get the gauges on first and see what they say.

Don't open a hot radiator unless you have a lever vent cap.
And then still cover it with a towel so if it steams/spits up you are covered.

From a cold eng...
Open the cap observe coolant level, fire it up and see how much the bypass is moving coolant, then either just let it idle till hot no cap, or set the cap on and turn it just to the first "catch" notch so it wont fall off but not seal up.
This way you can high idle it to hasten the warning.
Realize that when the stat opens it may puke a little.
Turn on the heater and wait for toasty warmth then you should be warmed up.
Go watch the flow again.

Okay, understood. Will try this once engine is cool.

Your fan clutch could be frozen up and causing the engine to run cooler. The problem I have with my truck, however in the heat of the Texas heat it never gets above 10 degrees pulling a fully loaded 23' livestock trailer ( with the air conditioner on, i might add.)..... Makes a heck of a noise driving around town, but no overheating issues.

I was thinking the same thing, however the fan spins freely.

This morning I did install a piece of scrap plywood that covers something like 1/2-2/3 of the radiator. According to the dash gauge it doesn't get any hotter than it did yesterday, but I do understand that can be unreliable. It does seem to come up to that lower stable point a little faster. We are also a little warmer today, probably about 40*F. Upper radiator hose and radiator do feel hot now vs warm yesterday. I can still hold onto both after driving and shutting the truck off.

 

[MJGenay]

Apologies, forgot to include the other information on my truck. I do have a pyrometer that came with my turbo kit that is installed. Climbing a medium grade at highway speeds I sit around 600*F on the EGT gauge, cruising is closer to 300*F. Temps on the dash coolant gauge are pretty steady unless I get on a long downhill in which case they'll drop a bit.

Timing is a little bit retarded, probably about a degree or two. Once I finally got the equipment to time it I found it was retarded quite a bit, I guess 6 degrees. Couldn't get the pump to twist further to advance it without putting undue strain on the injector lines and didn't want to loosen the lines as I plan to replace the injectors and pump. I have a new set of injectors from R&D and I'm waiting for a pump to be in stock there; once I can get one I'll get it all installed and dial in the timing.

 

[KansasIDI]

86 F250
7.3 IDI with Hypermax Turbo and more...
Idle water temp at 70* ambient, engine fully warmed, 170ish
Cruising water temp at 70 mph 70* ambient, 185* +/-5*
Idle EGTs 70* ambient, 280* settled
Cruising EGTs 70* ambient 70 mph, flat ground no wind, 800-850* depending on density altitude

91 F Super Duty (Service truck)
Water temp same as 86 F250, except in cold conditions, then this truck will hold temp better.
EGTs unknown at this time

Both trucks have new Spectra CU1165 heavy duty radiators, and precharged coolant. Service truck has coolant filter, still waiting on parts to add that to the 86. As of October 2023 the 86 got an entirely new cooling system with the fresh engine. Some parts were added earlier, but was finished with the engine.

 

[MJGenay]

Okay, I picked up the laser temp gauge today and did a little test. After driving around for about 25 minutes I pulled it into the garage, turned it off, and shot the upper radiator hose. Reading about 140*F. I'm going to guess the thermostat is stuck open. I have a replacement Motorcraft thermostat, gauges are coming in tomorrow. I'm going to do the gauges and thermostat at the same time as it requires dropping the coolant level a bit.

Temperature are around freezing and it's snowing a bit. If I'm understanding this wrong, please correct me.

 

[Cubey]

Okay, I picked up the laser temp gauge today and did a little test. After driving around for about 25 minutes I pulled it into the garage, turned it off, and shot the upper radiator hose. Reading about 140*F. I'm going to guess the thermostat is stuck open. I have a replacement Motorcraft thermostat, gauges are coming in tomorrow. I'm going to do the gauges and thermostat at the same time as it requires dropping the coolant level a bit.

Temperature are around freezing and it's snowing a bit. If I'm understanding this wrong, please correct me.

To test a new thermostat, submerge it in water and slowly bring the water to a boil. It should be fully open before it's a rolling boil. Then remove the pot with the thermostat from the stove and let it cool. It should close itself as the water cools off. If it opens and closes, install it.

No need to drain coolant just to pull the temperature sending units. You might lose a tablespoon of coolant, at most. Thermostat, yes, you have to drain a few gallons.

 

[MJGenay]

To test a new thermostat, submerge it in water and slowly bring the water to a boil. It should be fully open before it's a rolling boil. Then remove the pot with the thermostat from the stove and let it cool. It should close itself as the water cools off. If it opens and closes, install it.

No need to drain coolant just to pull the temperature sending units. You might lose a tablespoon of coolant, at most. Thermostat, yes, you have to drain a few gallons.

Thanks for the information! I'm debating pulling this replacement thermostat and checking it. Probably best to do, however, after reading that other thread that's going on right now I'm starting to wondering if my old thermostat was causing my truck to warm up abnormally fast in cold temperatures and this one actually is working properly.

 

[Cubey]

Thanks for the information! I'm debating pulling this replacement thermostat and checking it. Probably best to do, however, after reading that other thread that's going on right now I'm starting to wondering if my old thermostat was causing my truck to warm up abnormally fast in cold temperatures and this one actually is working properly.

I had a 27ft class C motorhome and for some reason, it tended to run 10°F cooler at very low speed than the smaller van I have now. Although, I did have the sender in stock temp gauge sender port on the motorhome. Same exact gauge pulled from it and installed in the dummy light port on the van. So maybe it's somehow a 10° difference between the two ports? The motorhome liked to run around 180 at idle, the van at 190. But perhaps the new (in '19) Motorcraft fan clutch that the motorhome got was much stiffer than the new Four Seasons one the van got so it ran the fan faster?

 

[Rocknit4x4]

I think your right that the port makes a small difference. I had an actual gauge in the factory sender port for a few months, then i decided i wanted both the factory gauge working and my real gauge - moved the real gauge to the port on the top of the water pump and the gauge seems to read about 5* colder now. I would have thought the coolant temp would be the same, but maybe being directly behind the fan / in the path of the air flow through the radiator its actually a little cooler there.