BMW M5 Forum and M6 Forums banner

1 - 18 of 18 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
Hello everyone I am new to the forum. I have looked around a lot trying to find a answer to how to prime the oil pump in my 91 M5. I have tried bumping the starter but I am not getting any oil pressure. I have read on the forum if you have a extra oil filter cap to drill a hole and put a nipple on it. This is my question because I have read different things in the forums. Do you pull a vacuum using the nipple like you are getting air out of the brake lines or do you pump oil into the oil filter housing. Thanks in advanced any help would be appreciated.
 

·
Registered
Joined
·
729 Posts
There are several ways.

- Prime it before you mount it (in a bad with oil and drive it with a electrical screwdriver, for example)
- Prime it before you but the sump on the engine (what I am doing, first before you mount the cylinder head and after it) No contamination enters the engine that way.
- Once the sump is installed it can take a serious amount of time until you see oil coming from the oil filter (once the cap is removed). It has no use to top up the oil filter housing because 1 way valves are installed and once you remove the center bolt that fixes the cap it will drain the filter housing (for that reason it has an o-ring at the end).

- In your situation, I would remove the oil filter housing and oil cooler. You will see 2 holes on the engine when the filter house is removed. Fill the lower hole (of 2) with oil and crank the engine backwards by hand (make sure you remove the valve cover to check timing after you have done this). After a few turns and some oil crank it the right direction. The oil pump should sufficiently be primed and pump oil. Put everything back and crank it (without spark plugs). Since the valve cover is removed you can also check if oil is getting to the head (camshafts, etc).
 

·
Registered
Joined
·
826 Posts
When I rebuild any engine what I do is exactly that in a bad/can put oil, sink the oil pump pick up, add oil thought the gears of the oil if necesary and the spin the gear until it start to flow oil, then I install it in the engine and yada yada.... Then when all is ready to crank for the first time, what I do is crank the engine with out spark plugs for two reasons:

1) Help starter to work easier and you battery

2) And maybe the most importan, even when is already coated the bearings in oil at the assamby stage, is mainly to avoid "the impact" of the cycle of compression in each cylinder and get probably a it of wear of the bearings while build up oil pressure.
 

·
Registered
Joined
·
208 Posts
When filling the engine with oil for the first time, I pump 2 liters of oil through the oil galley port on the front driver side of the cam tray to fill all the galleys, pour half a liter across the tops of the cams and chains and the rest fill as normal.

And as stated above, def. remove all the spark plugs, disable fuel pump and ignition and crank until the light goes off. Sometimes it takes a bit, but if everything is lubed up upon assembly, nothing can get hurt at cranking rpms.
 

·
Registered
Joined
·
826 Posts
When filling the engine with oil for the first time, I pump 2 liters of oil through the oil galley port on the front driver side of the cam tray to fill all the galleys, pour half a liter across the tops of the cams and chains and the rest fill as normal.

And as stated above, def. remove all the spark plugs, disable fuel pump and ignition and crank until the light goes off. Sometimes it takes a bit, but if everything is lubed up upon assembly, nothing can get hurt at cranking rpms.
^^ +2!

&

Oops! looks like I missed pointing out that step 2 requires to take off the DME/fuel pump/injectors relay (which ever) or just dissconect it the fuel injector connectors.
 

·
Registered
Joined
·
3 Posts
Discussion Starter #8
Thanks everyone who replied. The reason for this is due to the oil pump chain tensioner braking and falling into my oil pan. Since I dropped my pan I put new rod bearings on and rebuilt my oil pump. I have ordered a new oil filter hosing gasket since it seems I will be removing the oil filter hosing and I am hoping to get it done this weekend. Thanks
 

·
Registered
Joined
·
284 Posts
Bumping this thread because I have the same problem... no oil pressure. Nothing was opened on the engine, and it wasn't drained of oil. However, the front was on jack stands for a couple months, but not high enough of an angle that the pickup would have been unsubmerged.

So far I have read that the relief valve can get stuck open, but that it usually happens from gunk buildup. This car has always had short oil change intervals with synthetic and only has 132k miles on it, so I would be surprised if that were the case. Is it more likely that the oil pump has lost its prime from sitting on an incline? I get what Tomba is saying about removing filter housing, but why the oil cooler? Is he talking about the cooler in the bumper?

Looking at this diagram of the gasket, am I pouring oil in the small oval hole at the bottom? https://www.realoem.com/bmw/enUS/showparts?id=HD93-USA-09-1990-E34-BMW-M5_36&diagId=11_1267
 

·
Registered
Joined
·
681 Posts
If you've done nothing to the engine apart from store it for a short while at an angle (can't see how that would cause a problem once it's back on flat ground), I would check/replace the oil pressure switch first. Maybe the wire is corroded or not making a good connection?

Cheers,

Dave.
 

·
Registered
Joined
·
284 Posts
So just to update all places, I talked to Anri (west coast e34 M5 guru). He said starter RPM is not likely to be enough to build any oil pressure... Making my mechanical test gauge mute. He said that spinning the engine backwards with oil in the filter housing is futile (a myth) due to essentially no RPMs. Thoughts? He said that the best thing to do is to run the engine at 3-4000 RPM to force the oil pump to pickup oil and prime itself. I'm tempted to believe him because he is "the man" when it comes to this stuff. He also said that even if bypass valves stuck open, cold start oil pressure with some RPMs will override this valve and show pressure. This makes sense to me also. I think the relief valve being stuck open doesn't make sense because it usually get stuck open on startup when oil is thick and pressure spikes, so in the same case... it should be making pressure.
 

·
Registered
Joined
·
52 Posts
Alpine, I had a similar problem while doing a host of maintenance stuff. The engine sat dry for a few weeks. I put everything back together and boom no oil pressure. At first I thought it may just be the pressure sensor, nope. There was no oil in the filter housing (while adding oil I poured half a quart in the filter housing and coated the filter). I am far from the s38 guru but I wouldn't run the engine without oil for too long or rev it much past 1500. You could seize the engine/ brick it/ do serious damage. Through my research I was told that when these pumps sit dry for extended periods of time the seals dry out and cause failure. So for me it was replace the pump time. I had my mechanic install the new pump and was told the pressure returned instantly. I suppose you could try to rebuild the pump or these other "fixes" but up to you. I have my old pump sitting in my garage. If you interested in it I'd sell it for cheap.


I know it is an expensive part but the new pump was the fix. I found a pretty good deal from eEuroparts (considering what other outlets were asking for it), it was $400 for the pump. Everywhere else was around 5-6.

Good luck!
 

·
Registered
Joined
·
52 Posts
I get what Tomba is saying about removing filter housing, but why the oil cooler? Is he talking about the cooler in the bumper?

Looking at this diagram of the gasket, am I pouring oil in the small oval hole at the bottom? https://www.realoem.com/bmw/enUS/showparts?id=HD93-USA-09-1990-E34-BMW-M5_36&diagId=11_1267
The oil cooler lines tie into the filter housing and they need to be pulled/ moved out of the way to get the filter housing out. I think that's why he bring it up. The oil cooler itself can stay.
 

·
Registered
Joined
·
284 Posts
The oil cooler lines tie into the filter housing and they need to be pulled/ moved out of the way to get the filter housing out. I think that's why he bring it up. The oil cooler itself can stay.
That makes sense. It's looking like new pump time. I'm awaiting a new oil filter housing gasket, I'll give it one more start attempt, then it's going to be a new pump.
 

·
Registered
Joined
·
52 Posts
That makes sense. It's looking like new pump time. I'm awaiting a new oil filter housing gasket, I'll give it one more start attempt, then it's going to be a new pump.
Why are you doing the filter housing gasket? I'm assuming it's leaking? Funny enough that's exactly how I started down the same road. The goal was to replace the oil filter housing gasket. Of course it snowballed, like it always does, into replacing several other items. The motor sat dry for the few weeks while I was doing this and a host of other things and when I finally got it back together and bam, no oil pressure... Sadly, the issue was really just leaking power steering lines. It just appeared to be oil leaking from the filter housing but it was PS fluid coming from the main power steering hose that splashed onto the area near the oil filter housing. So check your PS lines...

I would be careful running the engine too much. No oil to vital components can cause serious damage. I did new rod bearing when replacing the pump and they were definitely needed. Not sure if you are trying to do this yourself or not but in order to get the oil pan out you'll need to support the engine and drop the front sub frame. There is just no way to wiggle the oil pan out with the sub frame still attached. I had my mechanic do the pump, while being fairly familiar with working on cars and having the tools. I am not a mechanic.

If your doing it yourself, best of luck. Keep us posted
 

·
Registered
Joined
·
284 Posts
Why are you doing the filter housing gasket? I'm assuming it's leaking? Funny enough that's exactly how I started down the same road. The goal was to replace the oil filter housing gasket. Of course it snowballed, like it always does, into replacing several other items. The motor sat dry for the few weeks while I was doing this and a host of other things and when I finally got it back together and bam, no oil pressure... Sadly, the issue was really just leaking power steering lines. It just appeared to be oil leaking from the filter housing but it was PS fluid coming from the main power steering hose that splashed onto the area near the oil filter housing. So check your PS lines...

I would be careful running the engine too much. No oil to vital components can cause serious damage. I did new rod bearing when replacing the pump and they were definitely needed. Not sure if you are trying to do this yourself or not but in order to get the oil pan out you'll need to support the engine and drop the front sub frame. There is just no way to wiggle the oil pan out with the sub frame still attached. I had my mechanic do the pump, while being fairly familiar with working on cars and having the tools. I am not a mechanic.

If your doing it yourself, best of luck. Keep us posted
Actually the car was down for a couple months for a steering box rebuilt (sent it to Miami), proper SLS delete, and AAS secondary air pump delete kit. I removed the filter housing per recommendation by Tomba in post #4 of this thread to remove it and pour oil into the block and spin the engine backwards. While the housing was off I could see that the gasket was completely compressed and oddly "smeared". I have an engine support bar arriving Friday and I've ordered a pump because I figure, even if I can get this primed, I don't want to go through this again when I store it for the winter.
 
1 - 18 of 18 Posts
Top