isuzu mu Oil and low Oil pressure at idle

[OdinT]

Hey
i got a 93 isuzu mu not long ago and thort i would give it a service
i changed the oil and stuff all went find but i noticed later on that the oil pressure at idle would drop off and the light would come on
i asked a mate at work who is a diesel mechanic and he sed that the isuzu do not use a oil with a high oil viscosity at higher temps
i also talked to a mechanic down the road and he sed that some of the newer isuzu use even a 0w 30 sorta oil
does anyone have any info on this
and what other things could couse this it was find befor the oil change and it only drops off after it warms up

[turnturn]

What oil did you use?
I have used 15w-40 (for diesel engines) oil in my 2.8 (4jb1-t) for over 200,000ks.

That low viscosity oil you mentioned above for the newer engines is not suitable for your engine.

[OdinT]

the oil i used is castrol magnatec diesel 15w 40

[geeves]

Unless the oil was faulty it will be perfect for the engine even if a little expensive and high quality. Do watch out for sythetics causing leaks though. They wash sludge out of places that were sealed by the sludge (not the oils fault) then small leaks occur. I ran Dello 400 for a while Magic oil for 5 changes then it started to leak. Changed to valvolene diesel extra and the leaks stopped.
Did you change the filter at the same time?
What age is the engine
How many km since the last change?

[OdinT]

not sure when last oil change was i just got the mu in like dec and it have no stickers or anything on it so i gave it one yea i did the filter at the same time there is only the one oil filter at the back by the firewall
its a 93 isuzu mu 2.8td according to the speedo its only dun about 113000ks
also for some reason today it has stopped dropping in pressure
i drove it to work and stayed at 2 mark on the gauge after it got warm so maybe it was a bit of stuff somewhere iduno
but if its working im not gonna mess with it too much i guess
thanks for the help too

[geeves]

very low mileage. Did you run a car jam report?
Could also be a bad filter or faulty (sticky)bypass. If its ok now its probably not going to be an issue

[varnz10]

Hi
Just a quick add on to this, I have the same engine.. different vehicle.. I have good pressure, being about 4 on the gauge when cold, and warm running at about 2.. only thing is when I sit at idle th epressure drops down to about-just above 0 like about 0.5. Any Idea on the cause?
Yes changed oil and filter, Valvoline Diesel Plus and a Ryco filter
No Idea what was used before hand.
Have changed the oil cooler to a 4jg2 one due to the way the exhaust runs through.


Thanks

[geeves]

first some confusion. The 4jb1 does not match either of the wagons in your profile.
What you describe is quite normal for a 4jb1 although it is a fraction low. Different oils give different results Which did you use. Also gauges are not known for great accuracy.
If its the 4jg2 then id does sound low enough to worry about Might have to test the pressure with a known good guage

[varnz10]

ok
was asking a while ago about putting a 4jb1 into my ubs69, as it had a failed engine. I have done this and so far, other than the low oil pressure it has been good. A little under powered under 2000 rpm, but that might have a little to do with the 3.1 turbo, once over 2000 rpm the motor pulls strongly and with the manual I think that there is very little difference if not a bit better than my wifes 3.1. and I have been getting much better mileage so far, but it is still on first tank so I am not sure but am looking at about 650-700 km a tank at this stage. but thats if the gauge is accurate. so I will have to wait. Thus I have a 2.8 with the 3.1 cooler and oil filter etc... So would the low pressure be acceptable in a 2.8? or should I get the pressure checked anyway

[geeves]

I would love to put the guage sender from a 4jg2 into a 4jb1 and see what happens. What you have is on the low side of typical but not so much that I would worry. Im guess ing you have the guage from the 4jg2 and sender from 4jb1. There could be a minor incompatibility.
On a side note just about all nissan patrols show 0psi at idle due to a sender fault. Nobody bothers about fixing.

[varnz10]

Actually transferred the sender and oil pressure warning switch over from the 4jg2 cause the wireing was different.
But so long as there is some oil pressure that should be good i guess.

Thanks

[OdinT]

hey all
so i had not been driving my mu that much in the past 12 months and thought the low oil pressure problem had gone away but now i have driven it to tauranga and back in the hot weather and the oil pressure is really bad like no pressure under 1500 rpm after its hot
so i have stopped driving it around on 1st start up its like 60 or 70 psi i have had the sender unit replaced and a new gauge on the dash, I have had the inspection plate off the sump and cleaned out the oil strainer and put it back together and still very low after it warms up im not sure where to go next and how hard the sump is to come off as the front diff and axle is right there.
what to do next ???

[isuzurob]

What oil are you running? if it helps i have a ubs55 that does the same thing oil pressure is better on agip oil though, has been like this for 5 years now and does around 200km a week its my hunting truck still going fine, im guessing the oil pump is sad

[geeves]

from memory you only have 113k on the truck. Vehicles with milages that low generaly have one of two things as well. Maybe both. Doctored speedo or a very poor oil change history. Either way in order of cost and difficulty.
Oil filter It might be faulty from new. Old one might of been blocked causing other damage
Oil filter bypass spring I believe this can be accessed under the filter but would need to check
Oil pump
bearings
The last 2 require sump off so engine out. It would be silly not to do both at the same time

[OdinT]

cheers for the reply what is a good oil filter that is sure to be good and if i take the whole filter housing off and clean it in some petrol will this be alright will the petrol not be too harsh on the parts or rubber bits
i have a feeling it is going to be the oil pump so something always not the easy thing to fix
if that is the case how hard is it to pull the engine and do things like piston liners all that sorta stuff its had a couple small oil leaks so i would not mind trying to find them and fix it all in one go i have not dun this sort of thing before is it better i pull the engine and send it too some one who can rebuild it and check everything i am sure i can manage to pull the engine out it will be putting it back in that will be hard lol

[isuzurob]

any branded oil filter will be fine on it, like i said agip super turbo 15w/40 has been the best in mine, oil pressure really good cold when its hot not so good but is higher than when it run on mobil 15w/40 bp 15w/40 and fuches 15w/40, its never going to fix the problem though, i dont mind if mine runs a bearing, pulling the motor out isnt that hard engine mounts are the worst part

[Roderunner]

Before you spend the cash on an engine rebuild try a heavier engine oil, 20/50 works well in the warmer months.

[geeves]

by a faulty filter I meant a dud one. All you can do is replace it and see.
Just as a side issue Does your temp guage work properly? If both faulty a earth fault could be the cause.

[OdinT]

hey
yea the temp gauge seems to work it never gets hot and stays below half almost all the time and the oil pressure gauge is a aftermarket one on the dash that seems to work fine
i am going to get a genuine Isuzu filter from Holden dealer on Friday that way i know its going to be right and there cant be any thing like wrong filter and such i hope
will pull the filter housing off the same time when i do the oil and filter then can see from there.
cheers for the help

[OdinT]

OK so i got the oil filter today its a genuine Isuzu one and it come with O rings, where do they go and how do i get them on as i changed the last oil filter and it did not come with any and it was hard just to get too let alone do anything else down behind the engine
guess it will not be soo bad as ill take the whole housing off btw is there anything i should look out for when i take it off like little bits that can fall out and go somewhere
cheers thanks for the help