David Smith

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May 29, 2010, 9:41:19 AM5/29/10

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Hi All,

I asked for help on finding a head gasket for a pathfinder (VW Diesel), but then realized I should discribe the system:

1) I did not see an increase in the oil level. I would expect to see an increase if the gasket was leaking.

2) Running the engine at high and low RPMs. Bubbles were coming intermittently at low RPMs. They come roughly every 15 to 20 secs, but it is not an exact repitiion. At times it takes 20 mins for the engine to warm up before I see a bubble. I increase the rpms, and do not see any increase in bubbles. In fact the bubbles disappear, then sometimes there were a few that show up, and then they disappear again. I went back to idle, and the occasional bubble reappears.

4) I shut off the engine, and the fluid level drops, again this does not happen every time.

5) I have replaced the fresh water pump.

My thoughts & observations

1) What gets me on this, is that if the gasket is blown, I would expect to see constant bubbling, and definitely any increase in bubbling as the engine RPMs were increased. The bubbles are not following this pattern. They are intermittent, and not always there.

2) Exhaust is normal, there is no steam, and when I touch the water, I do not feel any coolant or oil.

3) Engine oil level and the color is not changing.

4) I removed and tested the thermostat.

It has been suggested that I do a pressure test on the cooling system, no mechanic has this tool, and I can not find it. The parts are not readily availble to build one from scratch

Any suggestions?

Thanks

Dave

P40

Magic Carpet Ride

Jeff and Jane Woodward

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May 29, 2010, 10:10:53 AM5/29/10

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You might try talking to somebody at a radiator shop to see if they would come down to the boat to pressure test the system.

Have you had any overheating problems? I had a blown headgasket on the car and the first idication was overheating. I also wonder if you are loosing any coolant. Do you have to add coolant to keep the o'flo bottle full?

The coolant in a cruising sailboat engine has a long and tortured path. There are lots of little kinks and odd places in the system for bubbles to form and hide and eventually bleed out. The heat exchanger and the domestic water heater add lots of hose length and volume to the system. You have not mentioned when you first noticed bubbles, how big they are, or other things you have done to the system that might incur bubbles.

I hope this helps.

Jeff
Adagio, P-40 #109, 1986

Date: Sat, 29 May 2010 08:41:19 -0500
Subject: [Passport] Bubbles in the Expansion Tank
From: uml...@gmail.com
To: Passpor...@googlegroups.com

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Bill Schmidt

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May 29, 2010, 1:07:56 PM5/29/10

to David Smith, Passpor...@googlegroups.com

Check the hoses to/from the hot water heater. No leaks? OK, now bypass the heat exchanger in the hot water tank by connecting the two hoses. Now no leaks? You may get lucky. Oh, you could put red dye in the fresh water coolant and see where it goes.

Billy Manana

John Baudendistel

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Jun 1, 2010, 1:13:36 PM6/1/10

to David Smith, Passpor...@googlegroups.com

Dave,

Hello. You can check out the following to check for a blown head gasket. However if you had one you would have other symptoms which you have not described yet. One way to test for a blow head gasket is to use a "head gasket tester tool". It is a device shaped like a rubber glass cone. You warm up the engine somewhat, place tool over the expansion tank, add this blue die to the tool. If the die turns yellow it means that there is carbon dioxide or compression and or exhaust gases in the coolant system, indicating a blown head gasket. This is from memory but follow the directions. I bought mine I believe at a Nappa Auto parts store. Since on a diesel you cannot easily do a compression test to make the determination this is a way to determine via the coolant side. You should be able to get a coolant pressure tester from a Nappa Auto Parts store.

Also check all hose clamps and fittings. It is possible that you letting air in and coolant out at some connection. Are you losing coolant to the over flow hose or tank? If this goes to the bilge, put a small bottle on the hose to capture any which may be escaping the expansion tank. I added one and although I'm not overheating I sometimes get a small amount of coolant into the tank, which is then sucked back into the heat exchanger when the engine cools down. Otherwise on mine it would have gone into the bilge and shown a coolant loss.