Actual Operating Temp Issue

HARDTRAILZ

Original poster
Moderator
Nov 18, 2011
49,665
I knew my fan clutch was dying and had been seeing 230ish operating temp via Scanguage for a little while. This weekend I installed a new style 08 thermal fan clutch and am still seeing 230 as operating temp. I have replaced the thermostat and waterpump in the past year.

Is 230 in normal driving...whether 90 out or cool evening of 60...ok or am I missing something that needs fixed? I would think it should run cooler, but it does not act like it has any issue. My trans is staying at 190 with my aux cooler.

Any ideas from the great knowledge bank we call GMTNation?
 

HARDTRAILZ

Original poster
Moderator
Nov 18, 2011
49,665
It seemed by researching other posts that when it was bad the temps would run low not high.
 

jham

Member
Nov 20, 2011
1,334
HARDTRAILZ said:
It seemed by researching other posts that when it was bad the temps would run low not high.

true but I have seen on semi trucks that it can go either ways I will do some checking there should be a spec to test the sensor. You have changed every thing else.
 

HARDTRAILZ

Original poster
Moderator
Nov 18, 2011
49,665
Bit of Info..I run a basic 50/50 mix on the coolant. Generally prestone or generic. Have not done a full flush, but have drained and put in a couple gallons a couple times in past couple years. Fluid looks decent and not rusty or burnt.
 

Me007gold

Member
Nov 20, 2011
1,106
My scangauge usually has me at right around 202. Dose your MBD bumper restrict air flow at all? Even if it did would that affect it that much?
 

HARDTRAILZ

Original poster
Moderator
Nov 18, 2011
49,665
I am wondering that as well. With the body lift and bumper it may be restricting air flow and I will need to do an aux fan or somethng.
 

ScarabEpic22

Member
Nov 20, 2011
728
Thats really high, Ive seen ECTs of 220-224F once when towing up a steep grade in 90F+ heat. Not sure if your bumper is impeding flow, but 201-207F is normally what I see on my 02 I6 when logging it.
 

jham

Member
Nov 20, 2011
1,334
HARDTRAILZ said:
I am wondering that as well. With the body lift and bumper it may be restricting air flow and I will need to do an aux fan or somethng.

:undecided: I guess I should hook a scanner up to mine to see what it's actual temp is to see if If my temp is that high
 

Bartonmd

Member
Nov 20, 2011
545
There is absolutely less airflow than stock, and I do know that James Downing said his temps get a bit high since he put the 7" lights in front of his grille. I'm sure that it doesn't help that the air that does get through the grille can go around the radiator, because of the body lift gaps between the top of the radiator and the core support.

Like we were talking about offline, I suspect that the '08 temp-clutch fan just doesn't come on until a higher temperature, because I haven't seen the temp-controlled fans partially engage at much lower temperatures, like the OEM electronic controlled one did. My suspission is that 235 is the temperature that the later fan starts to come on.

The real way to tell, though, if it's an airflow issue or not would be to take the bumper completely off and drive around. That would net you much more airflow than even stock, and tell you if it's a water flow or thermostat issue, or if it's purely an airflow issue.

Mike
 

The_Roadie

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Member
Nov 19, 2011
9,957
Portland, OR
230 would totally concern me. My prediction it's 3/4 chance of a bad sensor, and 1/4 a clogged radiator or a mat of debris trapped between the AC condenser and the radiator. Not sure if it's easier to flow test the radiator or change the sensor. It's certainly not safe to get it up to temp, then take the pressure cap off and dip a thermometer or thermocouple into the radiator. Got a thermocouple you can install by taking off a radiator hose and threading it into the coolant that way?
 

Bartonmd

Member
Nov 20, 2011
545
I'm going to guess more than 1/4 change of clogged radiator... One time when Kyle came up to work to help me fab in the evening, it was after a wheeling trip, and he had a fan noise... Turned out that his fan was caked in mud...

Mike
 

HARDTRAILZ

Original poster
Moderator
Nov 18, 2011
49,665
Radiator gets sprayed out much more often and fan was just out and is clean. Be surprised if clogged unless it is internally.
 

Bartonmd

Member
Nov 20, 2011
545
You can't see the front of the radiator, and you can't really directly spray it, because the water gets slowed down by the condenser that's in front of it... A run around town with the bumper off will tell you if it's an airflow thing or not...

Mike
 

HARDTRAILZ

Original poster
Moderator
Nov 18, 2011
49,665
I pop the grill out to get to it.
 

Bartonmd

Member
Nov 20, 2011
545
I started to say that all you're spraying from the front is the condenser, but with the body lift, are the 2 separated enough that you can get a good angle from the top? Seems like you could get some water down there between the 2, but all you could really spray out would be the top couple inches?

Mike
 

HARDTRAILZ

Original poster
Moderator
Nov 18, 2011
49,665
I can get in there pretty good it seems, but will give it a good spray down and such before heading over tonight. Will see if that makes a difference.

Did think that I added the trans cooler and wonder if it is blocking some flow. May need to relocate it, but it is mounted like most others in front of the corner of the radiator. Would not think it would cause that much uptick.

I am sure it is the sensor or flow, but will have to try some things with the flow over the weekend to see whats up.

Appreciate all the help and responses!
 

Bartonmd

Member
Nov 20, 2011
545
If you're doing it with the hose at home, try spraying it out from the rear, through the fan...

Mike
 

HARDTRAILZ

Original poster
Moderator
Nov 18, 2011
49,665
That is usually the best way I have found. More mud comes out without jamming it into the fins.
 

HARDTRAILZ

Original poster
Moderator
Nov 18, 2011
49,665
Thanks everyone. I took some of the advice here and sprayed out the radiator and coolers really good. The radiator and condensor...not really dirty like I thought, but a bit of dirt. The new trans cooler...holy hell. It is a tight weave and it was packed full of bugs. Mr. Barton saw a little while back I ran through some nasty black bugs that literally coated my front end. It seems the bugs were just the size to pack full my trans cooler and thus reduced my airflow by about half. Sprayed all the nasty dead bugs out of the trans cooler and sprayed out everything else I could...

Woo Hoo! Temps hovered right around 195-205. The trans temps dropped from 190 to 170 as well. Never woulda dreamed those bugs woulda clogged up that cooler so bad. Glad it was something simple.
 

Bartonmd

Member
Nov 20, 2011
545
I was wondering when you were going to post here... Good to hear that it was just the plugged up trans cooler, and it's better now!

Mike
 

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