Hodor
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| posted on 23/5/15 at 04:56 PM |
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High oil pressure C20XE
This is one of those "I'm sure it never used to be like that" situations. I'm getting high oil pressure, or rather a large
variation in oil pressure. At idle I'm getting 40psi (2.7bar) but if I give it a bit of beans, either under load or just revving then the oil
pressure goes up quite swiftly to 80- >100 psi (5.5 to >7bar). Under normal driving, the oil pressure can be anything from 40 to 100 (which is
the upper limit of my gauge) at lowish revs or high - can't find a distinct pattern.
So I've replaced the oil and filter today (including engine flush stuff) and I've taken out the pressure relief valve and it looked OK -
can see some slight scoring, but it came out easily enough with no reason to suspect it was stuck.
I don't believe it is the sender or gauge as I'm getting a crap load of oil coming out (which is not normal) indicating the high pressure
is real.
Help please as I've no idea WTF is going on?
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Hodor
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| posted on 23/5/15 at 09:12 PM |
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took a video of pressure rise . Like I ask my doctor from time to time, is this normal?
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coozer
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| posted on 23/5/15 at 09:31 PM |
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Too much salt??
1972 V8 Jago
1980 Z750
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laptoprob
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| posted on 23/5/15 at 10:07 PM |
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I'd go for the relief valve first. With you saying its 'scored' a little i'm thinking it may be stuck shut.
http://www.youtube.com/watch?v=ajlF4nWJtGA
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Hodor
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| posted on 24/5/15 at 12:58 PM |
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So I'm thinking along the same lines, as the pressure can behave normally for a while, but then rise to +100psi whilst cruising in 5th at about
3k rpm. So I took the valve out again and sanded it with 1200 then 2500 grit.
Before sanding
 
oil pressure relief valve pre
After sanding
 
oil pressure relief valve post
so now nice and smooth, but still the same thing happens. Could be the channel it runs in is scored and doing the sticking, or something else.
Reluctant to blow £70 on a replacement plastic one, possibly better putting that towards a whole pump?
any thoughts anyone?
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laptoprob
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| posted on 24/5/15 at 02:10 PM |
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quote:
Originally posted by Hodor
So I'm thinking along the same lines, as the pressure can behave normally for a while, but then rise to +100psi whilst cruising in 5th at about
3k rpm. So I took the valve out again and sanded it with 1200 then 2500 grit.
Before sanding
oil pressure relief valve pre
After sanding
oil pressure relief valve post
so now nice and smooth, but still the same thing happens. Could be the channel it runs in is scored and doing the sticking, or something else.
Reluctant to blow £70 on a replacement plastic one, possibly better putting that towards a whole pump?
any thoughts anyone?
Ideally you could do with borrowing a good one from someone and swapping to see if anything different occurs. I may have one knocking about at work
that i can send you.
May be worth popping a little cloth up the inside of the valve too just to be sure.
Will let you know on the spare r/v.
http://www.youtube.com/watch?v=ajlF4nWJtGA
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laptoprob
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| posted on 24/5/15 at 02:14 PM |
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Do you have any noisy tappets at all? I'm just wondering if you have any blocked oil ways thats all as the oil pressure will rise when you rev
due to the flow increasing and the blockage creating a back pressure.
Oil flush or engine oil change may help here.
What grade do you use?
http://www.youtube.com/watch?v=ajlF4nWJtGA
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Hodor
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| posted on 24/5/15 at 02:17 PM |
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magic, thanks. Will try with a cloth.
I'm guessing Vauxhall parts dept should be able to get me one too if you have no luck. Not found one on the web except for the SBD plastic one.
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Hodor
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| posted on 24/5/15 at 03:33 PM |
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quote:
Originally posted by laptoprob
Do you have any noisy tappets at all? I'm just wondering if you have any blocked oil ways thats all as the oil pressure will rise when you rev
due to the flow increasing and the blockage creating a back pressure.
Oil flush or engine oil change may help here.
What grade do you use?
Hello. the engine sounds fine -no rattles or tappet sounds. I cleaned the pressure valve chamber with a rag and it's no different.
I was thinking a blockage as well -that was my first fix attempt - changed the oil with a flush treatment, new filter and some 5w30 fully synth - nice
and light.
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BaileyPerformance
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| posted on 24/5/15 at 08:15 PM |
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Has this just happened randomly? Or have you just serviced it?
Have you got a remote oil filter?
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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Hodor
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| posted on 24/5/15 at 09:02 PM |
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Randomly - actually, probably during a rolling road session on Thursday - took the car off the rollers and saw a shed load of oil on the floor (1/4 to
1/2 pint) which I think has been pushed out past the oil filter seal (I hope, and not higher up the block behind the cam cover).
Oil filter is in standard location.
So, in summary, since noticing the high pressure on the gauge (next trip out after the RR session):
1) added engine flush to the oil
2) changed oil and filter to 5w30
3) removed and cleaned pressure relief valve
4) removed and sanded down pressure relief valve
5) removed pressure relief valve and cleaned inside the valve chamber
None of that has stopped the issue
Next steps for me:
1) remove plug in oil gallery and blow through with some compressed air in case of a blockage
2) thinking of removing pressure relief valve and spring just to see what pressure I get with the bypass fully open all the time, just as an
experiment
Anybody got thoughts on the one way valve in the head to prevent the oil draining back down after switch off? Could it be sticking causing high
pressure - but then I'd expect to hear tapping from basically oil starvation in the head, which I certainly don't.
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02GF74
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| posted on 25/5/15 at 06:43 AM |
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Does oil pressure increase with rpm? Note perssure at idle, then at 500 rpm intervals.
Try a different brand filter, a long shot but filters have anti drain valve, usually is just a plastic membrane, could be duff one but highly
unlikely.
The relief valves usually are thimble shaped with a spring inside them, the oil prrssure works against this, eventually pushing the valve far enough
to open the relief channel, you dont mention a spring at all, is there one and does it look in good condition?
Can you try another oil pressure gauge?
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steve m
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| posted on 25/5/15 at 08:31 AM |
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I had a similar issue with my current xflow after a rebuild, but I had 90-100psi at tickover
I didnt dare rev it past 2k as it was obvious the pressure was trying to bend the needle on the gauge
I replaced the pressure relief valve and spring with an updated one, from Burtons ford, also gave the oil pump a good clean and blow through
its now pretty well around the 65 psi mark in normal driving, drops to 20 at tickover, but then creeps up to 40 ish when hot,
and at idle
I didn't replace the oil filter, but as suggested, for the price of one, perhaps you should
steve
Thats was probably spelt wrong, or had some grammer, that the "grammer police have to have a moan at
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Hodor
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| posted on 25/5/15 at 10:23 AM |
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I'll try and get the pressure vs rpm later, but I'm sure it's not consistent. It can vary between 60 and 100 psi at medium revs but
will try and quantify this later tonight.
I'm getting the same behaviour both before and after a filter change.
If it is inconsistent it has got to point to the valve sticking as opposed to a hard blockage?
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Hodor
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| posted on 25/5/15 at 11:03 PM |
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Can confirm inconsistent behaviour. Pressure of 70-80psi at about 4k revs one minute whilst on my drive then can be ~120psi at 3.5k whilst out on a
drive the next. Will always drop back down to 30-40psi at idle.
Got to be an intermittent sticking valve. Will order to SBD one as I read it was slightly under sized as well, which will help I guess if the bore is
scored.
Thought of sanding the inside of the bore with a bit of wet and dry, but wouldn't want to lose a chunk of it up the spout. But then "who
dares wins Rodney"!
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MikeRJ
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| posted on 26/5/15 at 06:28 AM |
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Is it an electronic gauge/sender? If so I would try to confirm the readings with a mechanical one, as they aren't the most reliable things.
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Hodor
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| posted on 30/5/15 at 08:00 PM |
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Update on all this...
Bought a replacement valve - didn't fix issue. Checked oil pressure with mechanical gauge and it's spot on. 80psi at 4k revs, just as it
should be.
In the process of all this, found that wire onto the sender was not well attached - re-crimped it on and everything is all good - oil pressure surges
must have been from the poor connection, which explains why on the driveway everything looked good and on driving I was getting wacky readings - must
have been going open circuit and reading high.
Also, found the source of the oil leak - the elbow connector for the gauge sender and oil pressure light T piece comes out the oil filter housing, but
it can't be nipped up tight as there would be no room for the senders (the elbow would point towards the block at full tightness). Fixed with a
wad of teflon tape. Bingo. Maybe look into getting a flexi to locate the senders so I can nip this tight.
Out for a couple of hours blat today - was awesome, especially as I've been thinking this was going to drag on and on...
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