Rebuilt 4.0 V8 no oil pressure

**rmalpas** · 20th November 2014, 08:00 PM

Have rebiult my 4.0 V8 and despite all new components just cant get any oil pressure on crank over. I removed cleaned and replaced the oil pressure releif valve and fitted a new set of oil pump gears properly lubed with vaseline and engine oil, was no wear on the old gears ( it must have been replaced at some point) have spent thousands on trhe motor and dont really want to start it till I know I have pressure. I pumped oil down the oil sender hole which seemed to end up just going straight to the sump as the level on the dipstick rose.... any ideas on what I can do without pulling the front off the motor and lowering the sump would be much appreciated..... am using a mechanical oil guage that connects into the sender hole.

Cheers

**p38arover** · 20th November 2014, 08:37 PM

Try removing the gauge and leaving the hole open and then crank the engine - just in case the gauge is faulty. See if you get oil flow out of the hole. It may well be messy!

**PhilipA** · 20th November 2014, 08:59 PM

Log shot but I seem to recall the timing cover gasket for a 3.9 and 4.0 are different, one having a blocked hole . Maybe worth checking whether each gallery has a corresponding hole.

maybe after other avenues mentioned are tried.
Regards Philip A

**p38arover** · 20th November 2014, 09:03 PM

If you are right Philip, that could be a nasty trap! Certainly worth looking into.

I recall some 300Tdi head gaskets didn't have a hole for the oil to go up into the head. (Pretty sure it was the 300 Tdi, I was helping with a rebuild where the mechanic discovered that.)

**Scouse** · 20th November 2014, 09:34 PM

Originally Posted by PhilipA

Log shot but I seem to recall the timing cover gasket for a 3.9 and 4.0 are different, one having a blocked hole . Maybe worth checking whether each gallery has a corresponding hole.

maybe after other avenues mentioned are tried.
Regards Philip A

I came across that when doing a camshaft on my old 3.5 injected motor. The later gasket had a hole offset that caused the oil pump to suck air instead of oil.

**justinc** · 20th November 2014, 09:55 PM

Yes, the ERR7280 is the correct part for serpentine belt engines, if you use the early one Err4936 you are left with a air leak due to an uncovered hole.

JC

**101RRS** · 20th November 2014, 09:57 PM

Originally Posted by PhilipA

Log shot but I seem to recall the timing cover gasket for a 3.9 and 4.0 are different, one having a blocked hole . Maybe worth checking whether each gallery has a corresponding hole.

Last week I put the timing cover on the 4.0/4.6 I am building - I wish I had know about this before hand - now I am wondering if I am going to have the same problem when I go to fire her up.

Garry

**Roverlord off road spares** · 21st November 2014, 01:39 AM

Originally Posted by garrycol

Last week I put the timing cover on the 4.0/4.6 I am building - I wish I had know about this before hand - now I am wondering if I am going to have the same problem when I go to fire her up.

Garry

Check the part number you used it ill tell all.

**lewy** · 21st November 2014, 08:29 AM

I had something similar after an oil change, no oil pressure,All i could find pointed to new oil pumps needing to be packed heavilly with vasaline not just smeared on.

**rmalpas** · 21st November 2014, 09:32 AM

should have been correct gasket, gears packed with vaseline Turner engineering reckons this is common and to start it and it should get oil pressure quickly... seems risky but might be worth a try at least for 30 seconds... everything was well lubed on assembly. Have removed oil sender but no oil spurts out...

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