Thermostat change?

[CScranton]

I have a 06 turbo diesel DRW 3500 with 53000 miles. I am changing and flushing the coolant. Should I change out the thermostat as well or wait for more miles. I use mostly for towing. Thanks..

 

[BigPapa]

I suggest leaving it alone.

 

[Motorhead]

DON'T use the factory radiator drain. I have read here that many guys have had them fail upon removal and not re-seal. A good idea is to completely remove the radiator so you can also back wash all of the cooling fins and don't forget to do the same to the AC condenser. The AC condenser stays in place.

 

[CScranton]

OK thanks. Just wondering when is the best time mileage or time wise to change. Also is Gates as good as the Cummins oe thermostat?

 

[CScranton]

I drained with the factory petcock 3 times so far while flushing and so far ok. I dont take it all the way out just a quarter turn or so to get a good flow, then tighten when drained. No leaks yet!

 

[Motorhead]

OK thanks. Just wondering when is the best time mileage or time wise to change. Also is Gates as good as the Cummins oe thermostat?

If your coolant has never been changed then you are over due. The factory coolant is a 5 year/100,000 mile coolant. I personally won't use any other thermostat than an O.E. Cummins replacement.

 

[CScranton]

Never been changed...

 

[p-Bar]

Thermostats usually don't need to be changed unless you have overheated the engine. The factory coolant is a bit better than the aftermarket. I didn't change mine till 150k. now I will do it more often. You have been lucky on that petcock , Have read too many horror stories.

 

[GrantP]

I read all of the horror stories too but I was very careful with the petcock and had no problems. Of course I've only had to do it once. If it won't budge, don't force it. I wouldn't bother with the thermostat.

 

[CScranton]

I opened mine for the fourth time to drain the final flush, it lets full flow out after less than 2 rotations of the valve, (I paid attention that time to the revolutions of the petcock valve) and after the radiator was empty, turned turned it back clockwise to tighten w/ no leaks. I think some guys might be trying to take the valve all the way out of the casing and when reinserting, running into problems. Mine was problem free on a ten year old truck. I read those same horror stories and was very aprehensive the first time I turned the valve. Got lucky maybe too!

 

[Prairie Dog]

I've had those drain valves disintegrate on other vehicles so with the horror stories I've heard here I won't use the one on my truck.
It's not a matter of being careful - they just fall apart if disturbed.

 

[p-Bar]

I've had those drain valves disintegrate on other vehicles so with the horror stories I've heard here I won't use the one on my truck.
It's not a matter of being careful - they just fall apart if disturbed.

Ya they are kinda like that spigot on the bottom of your waterheater

 

[AH64ID]

I highly suggest changing the thermostat.

The large size of the cooling system on these trucks tends to wear out thermostats faster than any other vehicle I have owned/serviced unless you regularly tow heavy.

The issue is that the OEM 190° thermostat cracks at 190° but isn't full open until 207° and 207° isn't easy to hit often unless your towing up grades regularly above 15K GCW. So what happens when the thermostat constantly only opens part way it that they develop a wear spot which then makes it more difficult to open fully when actually needed.

Get a genuine Cummins thermostat and replace it while you're doing the maintenance.


As for the petcock I have heard horror stories but I haven't ever had an issue with mine.

 

[CScranton]

Thanks for the info very interesting!