Blown 6.5 Diesel Van?

[tomg]

Hi there Im new to the forum.

I'm by no means a mechanic, let alone a diesel mechanic.

I can fumble my way around a gas engine and get it running again, but am basically clueless on diesel engines.

I bought a 1997 Chevy 3500 Express van with the 6.5 from a guy who said the engine was blown. The original for the van was to transplant the 350 from my other 2002 Chevy 3500 Express van but abandoned the idea of repair the diesel van. I got the van extremely cheap cause the owner said the van had a bad motor. The oil cooler came loose and lost all oil but he caught it before any damage was done, so he says. and the other probelm with it it was overheating.

Now I replaced the oil cooler and lines and it runs fine no bad noises and it builds oil pressure. It does over heat after idling for a few mins, and doesnt cool down when its being driven. the hose returning to the radiator is not hot so i assume its the water pump or the thermostat. Someone told me the 1997 6.5 had a dual thermostat design is this true? Any thoughts on my predicament is very welcome, and thanks for letting me be a member!

[trbankii]

That you got it running is a good sign. I know the ’97 and later trucks and SUVs had the high output water pump and cooling upgrades, but the vans are a slightly different animal and I’m not sure how they compare.

Easiest way to tell is the top radiator hose will go to the inlet that covers the thermostats. Should be fairly easy to tell whether it covers one or two thermostats.

[DmaxMaverick]

Yes, the single stat housing will be "O", while the dual looks like "8".

First, look for obvious leaks. Heater lines and core are common suspects. Also check the drain-cock and all hose connections (as well as hose condition). The van may also have plastic radiator tanks, which can crack. The tanks are inexpensive to replace. However, don't replace them if the core isn't good (replace the entire radiator). The radiator shop should inspect and advise.

Sticking stats can certainly cause the condition you are seeing. Other possibilities may be an air gap in the system (underfilled), and/or head gasket leak. Keep an eye on the coolant reservoir level, and check the upper radiator hose for pressure (when it shouldn't be pressurized, like right after a cold start, before the coolant reaches operating temp). If it's simply underfilled, some running with varied RPM's/temps will bleed it (keep the reservoir at "FULL"). The reservoir level should drop accordingly, but may not be evident until the engine cools.

[rustyk]

Don't rule out a bad temp sender - I wrestled with a 6.9L in my Ford van "overheating", but I put an IR thermometer on it and it was normal. Replaced the sender,and readings agreed.