Rad and Thermo Help

[Magnum5.9]

Since buying my 01 5.9 SLT 4x4 about 2 years ago I have noticed that it has been slow to get up to operating temp (especially in cold temps). For example this morning it was 30 degrees and I started it, let it idle in N (to prime the torque converter because I had them take out the check valve when I had new trans put in truck) for 5-6 minutes and when I got in it had moved about 1/32" off of the 130 degree hash line.

Then after those 5-6 min of idle, I drove to work, 1.5 miles away and it didn't get up to operating temp until I was about 3/4 of the way to work. During the trip I traveled at about 35-40mph at about 2000 rmps with a few stop lights.

I have also noticed that during the summer 90 degrees out side or so when I am climbing up a local 1000' grade (10 miles long), the temp will rise up to 210 degrees( if I am somewhat laying into it to climb the hill but with no trailer or load in the bed) and then it will slowly back down to around 190 then slowly back up to 210 degree

I haven't gave it much thought because I just figured both the slow warm up and the temp rise to 210 when truck was under load was due to large size of the motor and the fact that I do not have electric air fans behind the rad.

But I have begun to think that my thermo stat may not be 100% and may be a little corroded..? I would bust it out and look if it was not in such a cruddy spot! What do you guys/gals think?

Thanks!

 

[dudeman2009]

Since buying my 01 5.9 SLT 4x4 about 2 years ago I have noticed that it has been slow to get up to operating temp (especially in cold temps). For example this morning it was 30 degrees and I started it, let it idle in N (to prime the torque converter because I had them take out the check valve when I had new trans put in truck) for 5-6 minutes and when I got in it had moved about 1/32" off of the 130 degree hash line.

Then after those 5-6 min of idle, I drove to work, 1.5 miles away and it didn't get up to operating temp until I was about 3/4 of the way to work. During the trip I traveled at about 35-40mph at about 2000 rmps with a few stop lights.

I have also noticed that during the summer 90 degrees out side or so when I am climbing up a local 1000' grade (10 miles long), the temp will rise up to 210 degrees( if I am somewhat laying into it to climb the hill but with no trailer or load in the bed) and then it will slowly back down to around 190 then slowly back up to 210 degree

I haven't gave it much thought because I just figured both the slow warm up and the temp rise to 210 when truck was under load was due to large size of the motor and the fact that I do not have electric air fans behind the rad.

But I have begun to think that my thermo stat may not be 100% and may be a little corroded..? I would bust it out and look if it was not in such a cruddy spot! What do you guys/gals think?

Thanks!

Hunting from 190 to 210 is a little odd, but not a problem. Most chevy's from about 2004 run at 210 at idle. Its better for emissions. As for the warm up time, it may be old and sticky. Changing it wont hurt. As far as the cooling system goes, the 5.2 and 5.9 should be almost identical. I have a new thermostat in my truck and it can take over 5 minutes to warm up at idle.

The only time my engine has had a problem with the cooling system was when it was in the negatives here and the thermostat stuck closed. Fixed that by giving it a goof few revs.

 

[Magnum5.9]

Hunting from 190 to 210 is a little odd, but not a problem. Most chevy's from about 2004 run at 210 at idle. Its better for emissions. As for the warm up time, it may be old and sticky. Changing it wont hurt. As far as the cooling system goes, the 5.2 and 5.9 should be almost identical. I have a new thermostat in my truck and it can take over 5 minutes to warm up at idle.

The only time my engine has had a problem with the cooling system was when it was in the negatives here and the thermostat stuck closed. Fixed that by giving it a goof few revs.

Thanks for the input! I would happily change it out but with where they located these thermos, it seems like a bear and will take several hours of fiddling with

 

[dudeman2009]

Thanks for the input! I would happily change it out but with where they located these thermos, it seems like a bear and will take several hours of fiddling with

I cant remember if yours is located right where mine was, but it helps to remove the bracket that is right above it, even then you have to fiddle with the hose to get the housing out. Just make sure you use some gasket maker when putting it back in. I used the self sealing gasket and it still leaked, until I put some gasket maker in there. Also, don't forget to scrape off all the old crud from your gasket, mine was so bad there wasnt a gasket left, just a bunch of crap.

I'm at work and pulling up the service manual will take a few minutes,

Edit: Here is what I pulled from the service manual on how to replace the thermostat.
"NOTE: On air conditioning equipped vehicles, the generator must be partially removed.","Air Conditioned vehicles: Remove support bracket (generator mounting bracket-to-intake manifold) located near rear of generator","Remove accessory drive belt. Remove two generator mounting bolts. Do not remove any wiring at generator. If equipped with 4WD, unplug 4WD indicator lamp wiring harness (located near rear of generator). Remove generator. Position generator to gain access for thermostat gasket removal"

 

[Magnum5.9]

I cant remember if yours is located right where mine was, but it helps to remove the bracket that is right above it, even then you have to fiddle with the hose to get the housing out. Just make sure you use some gasket maker when putting it back in. I used the self sealing gasket and it still leaked, until I put some gasket maker in there. Also, don't forget to scrape off all the old crud from your gasket, mine was so bad there wasnt a gasket left, just a bunch of crap.

I'm at work and pulling up the service manual will take a few minutes,

Edit: Here is what I pulled from the service manual on how to replace the thermostat.
"NOTE: On air conditioning equipped vehicles, the generator must be partially removed.","Air Conditioned vehicles: Remove support bracket (generator mounting bracket-to-intake manifold) located near rear of generator","Remove accessory drive belt. Remove two generator mounting bolts. Do not remove any wiring at generator. If equipped with 4WD, unplug 4WD indicator lamp wiring harness (located near rear of generator). Remove generator. Position generator to gain access for thermostat gasket removal"

Thanks for that! So I have put on about 5000 miles since buying it 2 years ago and the truck has never overheated. Do you think the thermo is about shot or still has a while?

That just sounds like a pain to remove my ac generator and pully belt

 

[dudeman2009]

Thanks for that! So I have put on about 5000 miles since buying it 2 years ago and the truck has never overheated. Do you think the thermo is about shot or still has a while?

That just sounds like a pain to remove my ac generator and pully belt

The serpentine belt is easy in longitudinal vehicles, just get yourself a half inch drive ratchet and pop it into the square hole on your tensioner. The belt will come right off. The Alternator isnt super hard, but it is irritating. However, it isnt as irritating as removing the thermostat housing with the alternator still attached. IMO, it wont hurt to replace the thermostat. Just make sure you replace it with a 190 or 195 degree thermostat or your cab heat will suffer in the winter time. If you dont have a problem with long warm ups, dont even bother. It may have shot way up due to backwind killing the airflow through the radiator. Mine does that to me all the time when I patrol some of the industrial complexes. I'll be heading down an alley and the wind will match speed with me and my coolant gets up to 230 by the time I get out of the alley. No damage done so far.