Help ! no oil pressure - md2b

[saramark]

Can any one out there help.
My volvo mb2d (1972ish) has been running fine until this weekend when I started it there was no oil pressure. I have checked the seal on the oil strainer and dipstick but this has not helped - any ideas greatfully received
Thanks in advance

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[VicS]

How do you know there is no oil pressure? Do you have a gauge or are you relying on the warning light. Has the sensor for the light (or gauge ) failed?

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[saramark]

I have an oil pressure guage - which is not giving an reading. I dis connected the feeder pipe to the guage and would have expected oil to come up the pipe nothing - in fact any small amount of oil in the pipe ran back down it !

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[VicS]

Fair enough you've got a problem. You know about the seals on the dipstick and the strainer and are sure about them and of course the oil level is correct. We have a MD2 workshop manual but its on a friend's boat at the moment and neither of us is in commission at present. We've done a fair bit of work on an MD11C but we've never had to touch the lubrication system so cant help I'm afraid but it sounds like a pretty major job. I dont remember where the pump is located or how it is driven.

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[bedouin]

It could be that the oil-pump is not priming. As you know the seals on the dip-stick are critical as is relies on suction to prime the pump. I was once told that there was a hole somewhere to prime the oil-pump, but I have not found it.

I have had problems like this following an oil change, or if the engine has been standing for some time. In the latter case just running it at high revs for a couple of seconds sorted it - in the former it was necessary to remove the oil-pump, pack it with grease, and refit it - that sorted the problem.

The fact that you have had this problem with no apparent cause is worrying - it suggests a more serious fault, such as a worn oil pump.

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[PaulAG]

I also had/have this problem with MDIIC. However, with no pressure gauge and relying on the oil warning light, I checked that oil was reaching the valve rockers (removed valve covers and loosened one of the oil feed pipes - plenty of oil!). Checked oil pressure sensor off engine - applied air pressure from car foot pump - open circuit at ca. 10lbs pressure - all OK. I think either that following installing an Adverc battery monitor/charging system I inadvertently have earthed the circuit to/from the oil pressure sensor, or I have a more serious problem.
From memory of the service/workshop manual on the boat/at home (I'm not in UK at present), the only way of filling the oil pump (on the right front of the engine behind the alternator mounting), is to remove it and fill the chamber with oil and re-fit. You may be able to force enough oil down to the pump via the front feed pipe to the valve rockers, but it is a fine pipe and therefore slow. If the pump is not sucking, there could be a problem with the seals of the dip stick/fill pipe as one other replies has mentioned (most likely problem), or if the pump is worn, there may be too big a gap between the front face of the pump and the gears. Removing one of the shims (gaskets?) will reduce the gap, but see w/shop manual for the maximum/minimum gap.

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[Aeolus_IV]

MD2Bs do not have self priming oil pumps (or at least not when they are this old). You can prime the oil pump by unbolting it from behind the right hand side of the flywheel, then using an oil can (filled with your brand of engine oil) wind in oil by turing the "key" which engages with the end of the cam shaft. When oil starts coming out of the pump bolt it back on - quickly. I successfully did this three or four times getting the turn-around time to about 5 mins. However, when I had this problem with the engine it still eventually lost oil pressure, and we finally gave up and replaced the engine - too many problems, too unreliable. Sorry to sound negative. The MD2B is a good engine and there are many people out here who know a great deal about engines and how to keep them going. It is all a question of time spent finding the fault and the cost of repairs/parts.

If you think you need to replace your oil pump be aware that there are two very slightly different versions of the pump. Naturally not compatible.

If you want comments on how we replaced our MD2B then PM me and I organise some comment/lessens learnt.

Jeff.

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[VicS]

You' ll find another reference to this on http://motoren.ath.cx.

There was an article in PBO april 1997 on the MD2 which includes a picture which clearly shows the location of the pump (at least its on the outside not hidden inside somewhere). The little grey cells (both of them) seem to remember a posting on the subject on the forum a while back.

I would not mess about with the oil feed pipes to the rockers. (As sugested by PaulAG) We found one broken a few years ago, fortunately when stripping down for other work, because if you do damage one the head has to come off and the block lifted, if not removed, to unscrew the pipe from the crankcase.

Best of luck, but keep us informed of your findings and experiences of fixing it.

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[Aeolus_IV]

Yes, to replace oil feeds to rockers you'll need to lift off the cylinders as they screw into the block. I can say this with confidence as I still have the old '2B in the garage in about 20 or 30 component parts. It will come apart fairly easily in the event that more than rudimentary maintenance type work is required, but then you're into the realms of needing new gaskits etc etc when you put it back together.


Jeff.

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[PBrooks]

I had this problem with an MD1B. I found the easiest solution was to replace the oil pump with a secondhand unit. It worked fine after that, but I never did really trust the engine again...
Good luck

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[saramark]

Excellent help - I am going to replace the O rings on the dip stick and strainer and have a go at priming the oil pump ( without taking the Fly wheel off) Thanks for all the feedback and I will keep you all up to date

Steve

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[saramark]

Re: Help ! no oil pressure - md2b -SORTED

An update for all you fans out there !
- All O rings gaskets etc replaced
- oil pump stripped down, pressure release valve replaced and new gaskets
- oil pump primed with oil and replaced
Engine started and behold there was oil pressure.
I am away this weekend so hopefully when I get back to her on Monday evening and start the beastie up there will still be oil pressure (fingures crossed)

Thanks
Steve

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[Floating Weed]

MD2B No Oil Pressure

My MD2B has no oil pressure after coming out of winter hibernation. All I have done is change the oil. Reading the threads it sounds as though all I have to do is prime the pump (if I can find it) Or am I just being hopeful.

 

[Spondee]

Re: Help ! no oil pressure - md2b -SORTED

Steve-- I know this job was 14 years ago now, but do you remember if you managed to get the oil pump off without removing the fly wheel. I have an MD2B that seems to be experiencing the exact problem. I have put a new sensor on and checked the O-rings at dipstick and strainer, but the low pressure warning light is still on.
Any information you have about how you proceeded here would be very helpful.
Thanks,
Robert

 

[Spondee]

Re: MD2B No Oil Pressure

Floating Weed--
I wonder if you had any luck with this issue and how you proceeded? I have an MD2B that seems to be behaving exactly as described in this thread. Any tips on priming the oil pump would be very helpful.
Thanks,
Robert

 

[Kurrawong_Kid]

Re: MD2B No Oil Pressure

When I had an old MD 2b I had to recharge the oil pump a couple of times. It will come off without removing the flywheel, but if you have an alternator added, you will have to swing it out of the way and remove the belt. Both times it was after I had changed the oil.

 

[Spondee]

Re: MD2B No Oil Pressure

Thanks, Kurrawong. Good to know I'm headed down an established path. I DID manage to get the pump off without removing the flywheel. I'm going to clean all its parts while I wait for a new gasket for the back of it where it attaches to the engine (inside gasket was good). Hope I might ask a couple of follow-ups:

1. did you know you needed the recharge because of low pressure?

2. does recharging simply entail pumping oil into the intake at the back of the pump while rotating the gear key until you have a good flow coming out? (There certainly did not seem to be any substantial amount in the pump when it came off the engine.)

3. and then I suppose you try to get it back on the engine without too much oil falling back out?

4. seems weird that an engine would need this done every time the oil is changed! (more a confusion than a question -- I used the big oil refill cap entry rather than the two oil fill spots atop the heads)

Many thanks,
Robert

When I had an old MD 2b I had to recharge the oil pump a couple of times. It will come off without removing the flywheel, but if you have an alternator added, you will have to swing it out of the way and remove the belt. Both times it was after I had changed the oil.

 

[Kurrawong_Kid]

Re: MD2B No Oil Pressure

Thanks, Kurrawong. Good to know I'm headed down an established path. I DID manage to get the pump off without removing the flywheel. I'm going to clean all its parts while I wait for a new gasket for the back of it where it attaches to the engine (inside gasket was good). Hope I might ask a couple of follow-ups:

1. did you know you needed the recharge because of low pressure?

2. does recharging simply entail pumping oil into the intake at the back of the pump while rotating the gear key until you have a good flow coming out? (There certainly did not seem to be any substantial amount in the pump when it came off the engine.)

3. and then I suppose you try to get it back on the engine without too much oil falling back out?

4. seems weird that an engine would need this done every time the oil is changed! (more a confusion than a question -- I used the big oil refill cap entry rather than the two oil fill spots atop the heads)

Many thanks,
Robert

1 Oil pressure warning light did not extinguish!
2 More or less. I think I just poured oil in
3 Correct!
4 I deduced that the problem was wear in the pump which allowed the vacuum to fail and oil to drain back out of the pump to the sump as the oil is pumped out for the oil change. I seem to remember that on both occasions I pumped the oil out when the engine was hot. I always removed the big plug and washed the filter and then poured the oil in there rather than wait for ever for oil to drain down from filler plug. As mentioned above, the seals on plug and dipstick must be A1 at Lloyds.

 

[bedouin]

Re: MD2B No Oil Pressure

In theory it is possible to prime the oil pump without removing it from the engine - there is a hole just by the dipstick to do this - unfortunately on my engine I could not remove this.

Are you using the correct oil? I have only experienced problems when using Multigrade - if I used 30W oil it was not a problem.

 

[Kurrawong_Kid]

Re: MD2B No Oil Pressure

In theory it is possible to prime the oil pump without removing it from the engine - there is a hole just by the dipstick to do this - unfortunately on my engine I could not remove this.

Are you using the correct oil? I have only experienced problems when using Multigrade - if I used 30W oil it was not a problem.

Good thought which might explain why I had problems when changing multigrade oil when it was hot