Oil Psi Wtf?

[Orange Krate]

My wife's '99 Chevy Suburban has started getting oil in the radiator. Earlier this summer oil pressure started running low. I changed oil and the drain plug because it was stripped. Well the new one never sealed worth a flip. While we were out one day pressure went 0. I quick dumped in a quart because I knew it was low and the gauge pegged out.

At this point I'm figuring the sending unit went out. I change back stripped plug that still seals and maintain oil level. (i hear its hard job to change snd unit and so put it off to work on The General) Then the oil show up in water(no water in oil.) there's an engine oil cooler In the radiator so I'm figuring it's ruptured.

First things first go about changing the sending unit. After I find the sob I see it has come unplugged. I plug it back in and get this:
http://www.youtube.com/watch?v=1S1GtPKSrY4&feature=youtube_gdata_player

If this is real could that have ruptured the oil cooler? What would cause this pressure spike?

Signed,
Scratching my head in Texas

 

[Rustydog2010]

That indicates to me as a faulty sender or guage. If the cooler had ruptured you would loose pressure, not gain it. Coolant maybe under 10PSI where as oil should be at least 40PSI.

 

[OzFab]

I'm thinking faulty sender too. If the guage was giving you a true reading, you'd be cleaning up a huge mess by now

 

[FatCat]

Definately the sending unit. This is very common with GM vehicles. Just a few weeks ago one of my buddy's called me flipping out because his oil pressure guage was pegged. Was just the sending unit.
Oh and a 99. When your gauges all stop working just give it a good smack to the top of the dash. Works great. The 99's had all kinds of little electrical gremlins.

 

[anderkart]

If this is real could that have ruptured the oil cooler?

What would cause this pressure spike?

Signed,
Scratching my head in Texas

Dear Scratching my head,

Yes, your Suburban was available with a radiator that had an engine oil cooler built into the radiator, and that is most-likely the cause of your 'oil in the coolant" Issue. As a test, you could bypass the Oil cooler by disconnecting the lines (make sure its the engine oil-cooler side, not the tranny cooler on the other side) and securely clamping a section of high quality/high pressure, oil-resistant fuel (or hydraulic) line in place of the cooler.

Replacing the oil-gauge sending unit would be the easiest/most obviousness thing to try first, to repair your gauge issue. But sometimes the gauge itself can (and do) malfunction causing accuracy issues like your video shows. I have a gauge-tester that's made to test the accuracy of gauges like yours at the low, mid and high-point readings, but chances are you don't, so...)

There's also a possibility that your current oil-gauge reading is accurate, because your oil filter is plugged up, and the filter bypass valve is malfunctioning. This possible scenario would cause the engine to actually have extremely high oil pressure. (this scenario could also totally explain why the oil cooler in your radiator recently burst...)

If the truck is due for an oil change anyway: You might try doing that (and/or just a new oil filter), and then also bypass the engine-oil cooler in the radiator as a test. Then if the oil gauge reads out correctly, you've made your diagnosis without spending much money guessing at things...

Sighed,
Your buddy in Az.

ps:
If repairing your truck doesn't solve your head-scratching issue, get yourself a bottle of:

ASAP...

 

[Orange Krate]

I concur that it's the sending unit.

My theory on the oil in water is that when I had the leak and level went low I picked up some sludge. When I dumped in a quart it send a clot through my radiator oil cooler. The obstruction caused a pressure spike, taking out the already failing sending unit and blowing a hole into the water side.

Oil pressure being more than water this makes sense. Changing both today...well, chaning unit and checking radiator forsst anyway.

Thanks all!

PS. And thank you Anderkart on the other suggestion...I'm feeling much better now

 

[Orange Krate]

No, it's not the price of the oil I'm worried about it's the pressu.....Hey, wait a minute..You're a spam drone!

Sorry guys, I think I loured her(?) here with the word oil..

 

[fowler]

ha better fix it before it leaks
u might not be able to aford to fill it back up soon

that thing went and posted a few threads about expensive oil and just generaly ranted and raved

 

[anderkart]

I concur that it's the sending unit.

My theory on the oil in water is that when I had the leak and level went low I picked up some sludge. When I dumped in a quart it send a clot through my radiator oil cooler. The obstruction caused a pressure spike, taking out the already failing sending unit and blowing a hole into the water side.

Oil pressure being more than water this makes sense. Changing both today...well, chaning unit and checking radiator forsst anyway.

Thanks all!

PS. And thank you Anderkart on the other suggestion...I'm feeling much better now

10-4, you might just be right.
Be sure to let us know how your repairs turn out