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Discussion Starter · #1 ·
Have run into an odd problem. When you first start up the engine, oil pressure is good, well over 50 psi (maybe higher, had the son watch it). Once everything warms up, the pressure at idle drops to basically 0. Before an oil change, the oil light would also come on. Changed the oil and put in 10W-30. Have not driven it yet, only fan it up to temperature. Don't know the history of maintenance, however it has been sitting for around 7-8 years and has over 200K.

I don't think the sending unit is plugged as it does show high pressure at startup. I'm thinking of installing a mechancial gauge to compare and verify the low pressure but that won't happen for a week or so.

Another plan is to drain off a couple of quarts and replacing with 20W-50 and see what happens. Any other thoughts?
 

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I would go for the mechanical gauge, 0 oil pressure would sound like it was coming apart. A 7yr nap may well make for a faulty sending unit. Thickening the oil would only strangle the oil supply. These motors were designed with 5w30 tolerances in mind.

~psguardian
 

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Discussion Starter · #4 ·
88 Trooper II with the 2.6

I question the sending unit though since it works fine until the oil warms up. The pressure responds to engine rpm as well, so to me the sending unit is working. I would think that if it was faulty, it wouldn't be following the pressure.
 

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Senders on these are known to fail. Also the connector on the sender is not the best and they get corroded. It's just a little clip on a nail head for lack of a better description. Check that 1st. When the senders go they get flakey and then either default all the way up or down.
 

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Discussion Starter · #6 ·
Well we did the easiest thing, drained off 2 quarts of oil and put in some 20W-50, with not much success. When the engine got up to temperature, the oil pressure went down to almost zero - still no light however. I also opened the valve cover and saw good oil flow, however that doesn't mean there is good pressure.

I may just go ahead and order a sending unit just to have in case the mechanical gauge shows good pressure. I guess what baffles me the most is that it's good and high at startup and then it drops after things warm up. It hasn't been driven enough to even know if this has been happening all along, like everything else, we will solve it eventually.
 

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It's a heat triggered failure. These sewing machines would sound like a diesel 'bout to throw rod if thou really had no pressure.

You would have spun a bearing long since starting this thread lol.

Unscrew one of the oil gallery plugs down the filter side of the block & install a perm mechanical sensor/gauge.

~psuardian
 

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Discussion Starter · #9 ·
No, my son is dtill driving around with it. He did buy a mechanical gauge but we haven't taken the time to install it. He did buy another gauge cluster as well on the off chance that the problem is with the gauges, we'll see in a couple of weeks and update.
 

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If he has been driving around for 1.5years on low oil pressure, nasty things have happened inside. If its just a bad sender/wire/gauge you'll get a good reading once you swap out the offending item.

~psguardian
 
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