'76 Volvo penta AQ170C Leaking oil. Picture HELP!

[heryrg2711]

Re: '76 Volvo penta AQ170C Leaking oil. Picture HELP!

So one of the channels in the insert is leaking, very slightly . Do you guys know how i can test individuals channels? i tried to close one end of channel with my finger and push some compressed air into it, but thats a pain in the *** and not really working.

Anybody dealt with this or know any links?

 

[heryrg2711]

Re: '76 Volvo penta AQ170C Leaking oil. Picture HELP!

Found the leaking channel, it's the center hole that holds the screw. I'm thinking of several options. I'm gonna call/visit the radiator guy, see if he can seal it or recommend something.
Another option is to mill/drill-press out the current pipe and replace with a new copper tube and solder the top and bottom.
Also, i can just seal this whole tube, seal the bolt hole on the outside, and then just clamp the whole enclosure.
Another option is to get an oil filter adapter and set up a new cooler, re-route the water line to run through the radiator/cooler. A bit pricey and probably the best way to go but pain in the butt and too a bit too much $$.

 

[Scott Danforth]

Re: '76 Volvo penta AQ170C Leaking oil. Picture HELP!

having designed many thousands oil coolers (yes, I used to work for one of the manufacturers) I wouldnt recommend trying to repair a 30 year old oil cooler unless its a last resort, as the design life of a shell and tube heat exchanger is 10 years unless its designed with a rubber end sheet (for example, like cummins, caterpillar, and the Mercury Verado). your best bet is get a new core. the joints fatigue from constant pressurization (think of it like bending a beer can many many times). the baffles also wear thru the tubes if they are not mechanically bonded to the tubes.

Most manufactures braze the cores vs solder and then pressure tested in a test rig to test the integrity of the tube to header joints. on a removable core, the test rig mimics the housing and makes up the shell just to the o-ring seals on the cup. air or nitrogen is used in a test tank with either lots of light to see the smallest air bubbles formed, or in most cases for production its an automated pressure decay test.

a tested good core is then installed into the housing and tested again to test the integrity of the header to shell connections. 225psi oil side, 40psi water side is the usual test pressures for an oil cooler.

take it to your radiator guy. he will want the housing to use as the test rig if he deals with shell and tube heat exchangers. if he doesnt he will recommend a place to take it to, or he has someone in his network that does work on them. many may repair it, however most will get you a new core

 

[heryrg2711]

Re: '76 Volvo penta AQ170C Leaking oil. Picture HELP!

I understand what you're saying Scott. I know these were not meant to last such a long time and repairing one of these is still probably a losing battle, but i don''t really have a choice bacause the new insert is too expensive. I bought the boat for $100 so i'm not throwing down $700 just for this insert when i can fix it and run for a season or two.

In the long run i would want to put an oil filter diverter and and add a oil radiator/cooler.

 

[PiratePast40]

Re: '76 Volvo penta AQ170C Leaking oil. Picture HELP!

Your dilemma is not unusual for those of us with older boats. You can look for a cooler insert on e-bay or ask around locally. I only see one on ebay right now and the seller must think it's made of gold. You can also fashion a remote assembly yourself but you may find that it'll cost the same or more than a used one.

The picture with the inlet line pushed out of the cooler socket indicates that it froze at one time and ice pushed the line out. Not saying that's positively the case but it's strong possibility. You may have other problems such as cracked block or head so take it easy on expensive fixes until you get a good idea of total damage.

 

[heryrg2711]

Re: '76 Volvo penta AQ170C Leaking oil. Picture HELP!

So i went to the radiator guy, he said the only he could fix the hole is to pin-point it first which is impossible because there is no outside access to the tube. Long story short, he just sealed the bolt hole on both sides of the insert and also sealed the bolt hole on the outside cover. So i'm gonna reseal the insert and tie the whole thing with a screw-in metal tie down. I'm gonna do this today and post some pics of the this ordeal