07 GM 4.8

[dirtracr5]

Down to last resort, where can I find this stuff
thanks Mitch

Is 225 as hot as it runs?

Its got to 230 and thats when I stop it

If your actually getting combustion in the cooling system it will peg the gauge not just go to 230 when stopped. 230 isn't that hot. Sounds like an airflow issue. Condenser? Fan? Fan clutch?

[ParDeus]

PM me your address, I'll send a bottle of it to you, overnight it need be.

[JoePorting]

If you know you're getting combustion pressure into the coolant, and you already milled the heads and replaced the head gaskets, then the only thing left is that the block deck is warped. Maybe the person who had the motor before overheated it to death, and when they rebuilt it nobody ever bothered to check the deck.

[mitch]

Just drove van 60 miles it got up to 230 235 going up hills and would drop to maybe 225 coasting down hill.It would stay at 230 235 cruising at 70 75 mph.Got back to shop let it idle for 10 minutes `and it stayed at 230 sprayed water on rad an rev up to 1800 rpm temp dropped to 210 let idle for 30 min it climbed to 215. Shut it down and will check to see if it lost any water in the morning when it cools completely down.It never blew anything out the overflow that I am a where of. Still searching. Keep you posted. Thanks for all the responses
Thanks Mitch

[BLstangin]

Probably needs a fan clutch we replace them all the time at work if the fan is spinning very slowly at and idle it's junk.

[mitch]

Its got new fan clutch

it used maybe 2oz water maybe.

Been looking for a larger radiator but all I can find is a 1 inch core for both the 4.8 an 6.0 2500 3500 4500 all take the same radiator

Thanks Mitch

[JoePorting]

Are you sure the radiator is new? Maybe it was replaced with a used one.

[mitch]

Are you sure the radiator is new? Maybe it was replaced with a used one.

It looks new and the owner says ha replaced it twice. What gets me is if I do the combustion test it will not change colors until it gets over 220 so Im not real confident in the results.It acts like a restriction in the flow but I cant find where. Im sure it will turn out to be some stupid simple thing when i find it but im losing my ass right now.
Thanks Mitch

[mitch]

I let it idle for 75 minutes before I left work an it never got over 210
Mitch

[roc]

I let it idle for 75 minutes before I left work an it never got over 210
Mitch

Was A/C off?

[mitch]

I let it idle for 75 minutes before I left work an it never got over 210
Mitch

Was A/C off?

yes

[roc]

I let it idle for 75 minutes before I left work an it never got over 210
Mitch

Was A/C off?

yes

Although not conclusive, that's a good test result.

Have you thought about measuring the temperature differential between upper/lower radiator hoses, under hard driving conditions (long hills preferred)? That would indicate how well the radiator is working. For example, a partially plugged radiator results in smaller temperature differential. Same for bad fans. There are cheap digital multimeters these days that accept a temperature probe.

I'm afraid this sounds like combustion gasses leakage though. Hope not.

Good luck Mitch.

[In-Tech]

Some parameters.

Code: Select all

		Fan 1 On Coolant Temp.                                   108 Deg. C
		Fan 1 On Coolant Temp - A/C On                           140 Deg. C
		Fan 1 Off Coolant Temp.                                  104 Deg. C
		Fan 1 Run-on Coolant Temp.                               140 Deg. C
		Fan 1 Keyoff On Time                                       1 sec.
		Fan 1 On A/C Pressure                                  219.9 Psi
		Fan 1 Off A/C Pressure                                   150 Psi
		Fan 1 Off Vehicle Speed - A/C On                          35 MPH
		Fan 1 On Vehicle Speed - A/C On                           30 MPH
		Fan 1 On Minimum Engine Run Time                           1 Sec.
		Minimum Fan 1 On Time                                     90 Sec
		Minimum Fan 1 Off Time                                     1 Sec
		Fan 1 Turn On Delay Time                                 0.3 Sec
		Fan 1 Turn Off Delay Time                                0.2 Sec
		Fan 1 Off Delay After Fan 2 Off                            1 Sec
		Fan 2 On Coolant Temp.                                   113 Deg. C
		Fan 2 Off Coolant Temp.                                108.5 Deg. C
		Fan 2 On A/C Pressure                                    310 Psi
		Fan 2 Off A/C Pressure                                 230.1 Psi
		Minimum Fan 2 On Time                                    210 Sec
		Fan 2 On Delay Time                                       10 Sec
		Fan 2 Turn On Delay Time                                 0.2 Sec
		Fan 2 Turn Off Delay Time                                0.3 Sec
		Fans Off Vehicle Speed - A/C On                           45 MPH

[In-Tech]

And all of that area starts near this address. $00009430 specically $00009434 16 bit value

Code: Select all

0100 00CD 7F80 0433 0055 00F0 00D8 00C0 
00B0 00A8 00A0 00A0 00A0 00A0 00A0 00A0 
00A0 00A0 00A0 00A0 00A0 00FF 03B6 06FF 
0800 3700 3025 0100 0000 0000 0000 0000 
0000 00A0 01E0 1C00 3100 03E8 0900 0100 
0000 0000 0000 0000 0000 0800 099A 0B33 
0CCD 0E66 1000 1000 1000 1000 1000 1000 

[mitch]

Has anyone ever checked the pressure in a cooling system to watch the pressure as it warms up an when you rev the motor.I put a gauge in the head and it will go up to 30 35 psi when I rev it but it comes right back down.I have about one more day that I am going to waste on this and then just take my loss on this job.
Thanks Mitch