experience with pressure testing cooling system?

I thought I needed to broaden my post in order to get any useful input some one may have. Would anyone who has pressure tested their Sprinter cooling system please share some of the experience? I am looking for what is now a small leak that drips onto the lower edge of the engine block on the driver's side of my 06 Sprinter--just about under the small hose that connects above the drip. I have tightened all clamps and the leak continues. I can't see anything actually coming out of a hose, head gasket area, or water pump.

What test unit and adapter have you used? Was the procedure successful in finding the leak? I only have about 31,000 miles and no codes are showing on my DAD unit.

Hi James,

I have used a home made pressure tester which attaches onto the top of the coolant header tank. It is made from various bits of plumbing fittings and a pressure meter on the top. I have attached an air line from a compressed air unit and set the output of the regulator to 10 PSI. The rig is then left for one or two hours to allow any leak to show. MB recommends not to exceed 20PSI. Clean up any fluid that you can see on the outside of hoses and fittings first.

In my case there was a loss of fluid which was not apparent until the Check engine light showed and on inspection, the coolant level had dropped to below the sensor level in the header tank.
On inspection there was no sign of coolant loss. Topped up the fluid and all was well. However, about 400miles later the check engine light showed again and the coolant level was again down to below the sensor.

After applying the tester for a few hours, two drips of coolant was seen on the engine block just below the water pump. The leak was subsequently found coming from the front seal of the coolant water pump. The pump was replaced and all is now well. The van had done about 185,000km before pump replacement.
I suspect, in your case that it is not the pump but something closer to the coolant header tank. I am not familiar with your engine, but have a look around the fuel line heater and the Aux heater hoses and pump.

Cheers

Ross

Thanks, Ross. The hint about leaving the test on for a good while will help. My wife and I visited Nelson a couple of years ago--along with most of the south island-- to tour and mountain bike. What a great place and people! We hope to get back sometime.

JamesM said:

I thought I needed to broaden my post in order to get any useful input some one may have. Would anyone who has pressure tested their Sprinter cooling system please share some of the experience? I am looking for what is now a small leak that drips onto the lower edge of the engine block on the driver's side of my 06 Sprinter--just about under the small hose that connects above the drip. I have tightened all clamps and the leak continues. I can't see anything actually coming out of a hose, head gasket area, or water pump.

What test unit and adapter have you used? Was the procedure successful in finding the leak? I only have about 31,000 miles and no codes are showing on my DAD unit.

Click to expand...

I got tester at autozone I think used 20psi but to long ago.found leak on heater valve small leak. Ck with hand on hose for water. Running down hose if dripping at block. By torbo res.

Hi James,
Yes it is a great place to live. We are having a couple of forum members from Arizona to house sit and look after the cat for two weeks while we are away in the North Island. They have a motor home similar to ours.

Hope you find your leak.

Cheers

Ross

Update--FYI, we used Snap On tester. It installed without using an adapter. The test dropped about 1 psi (from 15 to 14) in a little over an hour with no apparent leak. I was told this level of drop was not unusual for a good system. Running the engine produced no fluctuation and the oil is just at full with no cloudiness. I also drove for an hour and found no leak. I will keep my fingers crossed that tightening the clamps helped but I'm not usually that lucky. If the leak re appears I will leave the pressure on for a much longer time and see what happens.

any word on this?

As of May 19,2011 (+5months and about +4000 miles), the leak has not recurred. Tightening the clamps in the area has worked so far.

Resurrecting a old thread with a similar problem. Going from max to min in my coolant tank in a few months or so I don’t use it that much. Put a pressure tester on it and it drops from 15 to 10 psi in 24 hours. I’m thinking this is not much to worry about it could be leaking out of tester slowly It’s only a cheapy eBay job. Think I’ll buy a new genuine radiator cap and maybe try the overflow catch can test in the mean time?? What you guys think?

burns said:

... What you guys think?

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Sounds reasonable to wait.

Some things to consider.
If the leakage persists inspect for white residue trail down by the water pump.

Next oil change inspect for water in the oil or boil a bit of the used oil in a pan to watch for steam. (Only do that when Momma's not in the kitchen. Don't ask... )

vic