Volvo Penta MD7a Water cooling system

[Scubaseas]

69A and or 69B

https://www.marinepartseurope.com/en...26-13636D.aspx

[MicHughV]

I had that same engine....those fittings are a royal pain in the arse.....I had the same problem...could not get them to fit right and they leaked...

what I did was to make two cuts in the copper tubing about 4" or so away from that fitting....and with about a 3" gap to the next cut....then I spliced in a rubber hose to each end of the copper pipe...and clamped it on with a hose clamp...

this way I could fit that copper tail and rubber fitting perfectly into the hole where it needed to go...and let the rubber hose give me enuff flex to continue the to the next run of copper tubing....

never had a problem after that...

[Scubaseas]

It helps to have the right o-ring seal also. Which usually does not come with the pump rebuild kit. One source


https://www.fcpeuro.com/products/vol...gaAh58EALw_wcB

[hpeer]

69A or 69B on the exploded parts diagram.

https://www.marinepartseurope.com/en...26-13636D.aspx

And the funny looking squares with half circles cut out in the Ebay pump rebuild kit link I posted above.

[MicHughV]

yes, you can buy those rubber fittings from Volvo at $234,435,999.00 each.
or....
you can go down to your local hardware store and get the same size rubber o-rings that that will work just as well....for about 0.10c each.....
oh...
and before you buy an oil filter from Volvo...at $676,556.00. each....you can get a variety of same size oil filters from your local auto parts stores...

one thing all Volvo engine owners have in common....they will swear on all that is holy that it will be their last Volvo engine...ever !!!!

I was looking at boat once that I really liked...opened the engine compartment.....and there it sat in all it's vile green color...a Volvo....I shuddered at the sight....got sick to my stomach....nauseated...trembling....I had to be led of the boat.....was too weak kneed at the sight...true story...

[Scubaseas]

A nice water pump rebuild kit.

https://www.ebay.com/i/112375767496?...YaAh3kEALw_wcB


Here is the exploded parts diagram.

You are looking at parts 69 and 70.

https://www.marinepartseurope.com/en...26-13636D.aspx

Nice kit indeed. The cavitation plate is nice to have. The o-rings are not included in the ebay kit however. Those are the shaft seals. Parts 69 and 70 are not in the kit. The seal from FCP is $0.35 each. Yes Penta OE parts are expensive but an OE Mann oil filter (which is who makes them for Volvo) can be had for about $6.00. Just because it's green doesn't make it bad. There are a lot of 50 year old Volvos out there running just fine.


Yes a standard o-ring will work but not last as long as the proper part as the sealing area is much less. If you put it together the way it's supposed to be you won't have any problem with it working properly.

[Scubaseas]

yes, you can buy those rubber fittings from Volvo at $234,435,999.00 each.
or....
you can go down to your local hardware store and get the same size rubber o-rings that that will work just as well....for about 0.10c each.....
oh...

You can buy an OE Volvo o-ring at any Volvo car dealer for under $3.00. It's the same oring as a heater pipe to water pump pipe on any 444, 544,122, 140, 240, 740 760, s90, v90 car or any b18, b20, b230 engine. It's listed in the climate control section, not the cooling section of the parts catalog. Or any FLAP store will have water pump gasket kits that will also have it but they run about $10. While a standard o-ring may work in the short run it has a much smaller sealing area and does not hold the pipe in place like the designed square cut oring does.



I wonder if people's bad experience with Volvos is they simply weren't fixed right?

[hpeer]

I wonder if people's bad experience with Volvos is they simply weren't fixed right?

When I bought my boat the engine was fresh off a total rebuild. Thanks think the mech that did the rebuild did a good job. Whoever installed it in the boat should have been shot.

[MicHughV]

I've had the the distinction of having had to deal with two different Volvo engines...both brand new....
I don't know how clear I need to make this...under no circumstances would I ever consider a boat again powered by a Volvo...even if the boat was free, but was powered by a Volvo....I would walk...
But that's my opinion.....the MD7 engine for starters....is sea water cooled....enuff said...
Buying parts generally requires you to rob bank first...
What's the point belaboring this issue....not for me....for others...maybe...but for me, no !!

[hpeer]

Well these MD7’s have a good reputation for being bullet proof. So far mine has. I had to rebuild the water pump, but parts were cheap and readily available.

I did have to replace an exhaust elbow, but in that case I made my own and a spare. Not pretty but it works.

AND, I bought a second motor for $250 so I have a complete set of spares. Maybe not readily available depending upon where I’m cruising but that’s with any motor.

Mostly the problems Ive had with the engine are related to the install. Some really dumb stuff there. Because of my inexperience it took me far too long to work them out.

Now these comments are related ONLY to this little green monster. I’ve no opinion on other models, so your opinion may be correct with them. Don’t know.

There are idiocyncracities for sure, this silly water washer being the most common, but once you understand they are generally great little motors. You can even crank start them, zero electricity required.

Not for everyone, but I’m fond of mine.

[MicHughV]

I will grant that the MD7 engine is bullet proof.....I had seawater enter the cylinders and everywhere else....seized up solid...took the cylinder head off....sucked the water out....beat on the piston with a sledgehammer till it reached dead bottom...buttoned everything up...used same gaskets...some new oil.....cranked right up....smoked a wee bit....but....amazing....just kept going....but cleaning out all the water jacket cooling passages from time to time plus a myriad of other " little" things...drove me nuts...
and you can still start it by hand...I'll give it that...but......???

[JD-MDR]

Originally Posted by Toddy693

Where is the bolt located that secured it?Can’t seem to find one?

The brackets 69 A&B hold it to the water pump and that's all I have. I had problems getting a seal. I pulled the pipe off and bent it a little so it would have some pressure to hold it in place. It's been holding up pretty good . There iwas a little sign of water stain but no visible leak and its a lot better than it was. I think it sealed itself . I painted everything about 100 hrs ago and the staining is pretty much stopped.

[hpeer]

IIRC they are held by the same screws fhat hold the cover?

Is that true?

When I got the engine the PO had a speed seal on and had discarded the hold down clips. It was only when someone gave me an old pump I realized what I was missing.

[jamhass]

Originally Posted by Toddy693

Where is the bolt located that secured it?Can’t seem to find one?

No bolt. Many of these joints are sealed only by "geometry", that is, the rigid pipe is held in place by the fact that it is "clamped" between two (or 3) immovable objects.

Thus, to remove or reinstall the pipe and/or seals, at least one of the attached objects (water pump, etc) must be at least loosened. Bending the pipe to install without loosening the other parts will usually result in a leak, possibly a permanent on due to damage to the pipe sealing area.

Some of these joints are secured with a bolt and support plate, but these usually have the U-cross section seal.

[barnakiel]

There that thing made by e.g. NURAL that is called liquid gasket. It is heat proof, waterproof and oilproof.


Google for 'liquid gaskets for engines' and relevant local brand will pop on your browser.



I used it in various spaces on our engine and it seems to do the job very very well. You can seal any shape fitting with it.


b.