Blown Oil Filters

[hairy bear]

Hi! I'm new to the forum and a new diesel owner. I recently bought a 1997 GMC 3500, 2wd, crew cab, 6.5 TD. The truck was purchaswed in Dallas and I drove it home to Utah. The first night was spent in Lordsburg, NM where the temp dipped down to 20 degrees. That morning I started the truck before pulling out of the parking lot when a man began waving his arms and pointing to the truck. After shutting it off I saw a large pool of oil beneath it. The filter o-ring had blown out. I pushed the truck back a few feet and bought a new Delco filter and 7 qts of Rotella 15W30 oil and refilled. It blew again after starting. The pressure gauge, at idle, was pegged at 80 psi+. I called the local Chevy dealer and had it towed. He changed the oil and filter again. He then started it and let it idle for some time. Next he roadtested it where it again blew a filter. Next he replaced the oil and filter yet again and plugged the heater in inside the shop where it spent the night. Next morning he started it and let it warm up, test drove it and I headed home. My question: Is the high pressure normal in cool weather? The pressure gauge read 55 lb at 2000 rpm and 35 lb at idle on the way home in 80 degree weather thru Az. Since it still pegs the guage at idle after starting, I'm a little nervous. Can anyone help on this?

[suburbanz]

sounds like something is wrong with the oil pump i am sad to say.i think you can get the pans off these trucks with the engine in the truck to service the oil pump.

[JohnC]

Sounds like the oil pressure bypass valve is/was stuck. It takes a LOT of pressure to blow the filter off, like 150+ psi. I'm pretty sure you can get at the valve from the oil filter pad on the block (remove 4x4 adapter) but best to doublecheck before proceding.

[tom.mcinerney]

The Helm manual describes procedure for removal, cleaning, replacement of pressure regulation/bypass valving in block under(above) oil filter. May need to buy new replacements...?

[suburbanz]

so they are not built into the oil pump i dont guess?that is what i was talking about but all the one ive seen have been built into the oil pump.anyway good luck with the problem!

[hairy bear]

My thanks to all who have replied. After the snow stops and the driveway dries (darned crew cab/long bed won't fit in the garage)I'll remove the filter and the pressure relief and clean everything out. Maybe even crank it over to see if that dislodges any blockage. If I'm unsuccessful I'll drop the trans and jack up the back of the engine and drop the pan. Thanks again, guys!

[Bobbie Martin]

If the oil pressure relief valve is sticking, that usually suggest dirt or debris has scored it or is stuck in the valve. Which means the truck maybe didn't get serviced regularly. I might be tempted to do an oil analysis at the next oil change to see if there are any problems developing. I'm not sure this is applicable to the 6.5, but one thing we do on the Minis is replace the oil pressure relief piston with a suitably sized ball bearing. Its less likely to stick. You have to shorten the spring when you do it or you will have way too much oil pressure. You might want to see if you can do something similar.

[tom.mcinerney]

Suburbanz raises a good point. It may be the valve in the pump, or it might be one in the block at filter pad. Suggest study lube scheme before/as proceed. Good first step--talk to knowledgeable dealer(or parts man, engine builder) to see if there is a regulator in the pump .
Spinning the oil pump driveshaft with a drillmotor on a modified pumpdrive might help at some time.
When i acquired mine, i was cautioned that the orings in the 4*4 oilfilter 90* adapter tended to blow out. I remoted the filter, got rid of adapter. In process, i noticed that the seal(oring or square ring) between the adapter[or filter, in a 2wd] and block BARELY skirted the edge of the (block)mating flange. If yours is machined as poorly as mine, there's a chance that the problem concerns the fit of the seal; the oil pressure might be fine. In this regard be mindful that many 6.5L drivers only use the oem cluster gauges for comparative readings. For an accurate measure many have installed dedicated aftermarket gages. Suggest check adapter seal (i put white pipe dope on it to follow track). Good luck, keep us posted.

[ 01-03-2004, 06:52 PM: Message edited by: tom mac 95 ]

[Gapper_ca]

Tom what parts did you use to remote locate the oil filter. i have wanted to do that with mine as it is a 4X4 and is a real pain to change the filter.

thanks