2002 V6, bubbles in coolant tank and oil leak

[Majorcnut]

Hoping someone familiar with the V6 engine can give me some advice.

Two weeks ago I purchased a 2002 V6 Chamonix with around 123,000km on the clock. It is advertised in the trader section of this site still and was located in Kelowna.

The seller imported it himself a few months ago, had been driving it around and assured me it was in great condition, hence the higher price then most V6 Delicas around.

Two things I noticed before I purchased it were a small amount of fluid of some sort had dripped onto the transmission lines going into the radiator, and a green stain on the top right of the coolant header tank. There was no visible leakage from the coolant tank, so I figured it may have been spilled coolant or wiper fluid. All fluid levels looked ok.

Ended up buying it and driving around 700km back to Prince George. Van drove nicely, temperature gauge stayed below half, used around 11.5L / 100km. Engine is kind of loud under hard acceleration, but I have no idea what these V6 engines are meant to sound like.

It sat in my garage for about a week. Next time I looked at it I found the coolant tank was empty, oil and other fluid levels ok. There was still coolant in the hoses connected at the bottom of the tank, so it didn't run dry. Filled it up with about 1.5L of coolant and bled the system.

Had a mechanic look at the van, he pressurized the cooling system found the coolant tank was leaking at the top right corner where the green stain is. Also there is a minor oil leak somewhere, seeping out of the engine behind the alternator, then running down the back of the alternator and dripping onto the transmission lines where they run into the radiator.

For now I have sealed the coolant tank up with JB Plastic Weld, currently it is holding pressure, and doesn't seem to be using or leaking coolant.

What has me really worried now is the air bubbles in the coolant tank. Tonight I bled the system, letting coolant out of the plastic bleed bolt above the battery with front and rear heaters on max. I then filled the coolant tank to the brim so I could get a good look at the bubbles. My guess from googling is that this is not normal, and maybe a sign of a blown head gasket.

I took a video and put it on youtube:

https://www.youtube.com/watch?v=EyFzCTvM8Mg

Has anyone seen bubbles like that in a V6 Delica before? Could it just be air that is still trapped in the cooling system?

Thanks for any advice,

Dave

[Growlerbearnz]

The expansion tanks are known to crack, there's even a guy who makes aluminium replacements: http://www.tigweld4u.com/delica-expansion-tank.htm. You will need a new expansion tank at the least.

Bubbles in the coolant aren't a good sign. What usually happens is coolant tank cracks, coolant leaks out, engine overheats, head gasket fails.

I'd test the bubbles for hydrocarbons using a test kit like this one: https://www.amazon.com/dp/B06VVBSFTF/re ... il_0?psc=1. Here's how it works in practise: https://www.youtube.com/watch?v=CHp5E7XnbXo (skip to about 6 minutes to avoid all the blah blah). That'll tell you if the bubbles are exhaust gas.

[Majorcnut]

I have ordered a replacement tank on eBay, $87 with shipping from Lithuania. The listing says "Quality: very good, made by serious manufacturer", but I'm not counting on it. May look into an aluminium one in the near future.

I've got it booked in at a mechanic on Friday for them to test the coolant for exhaust gases. Fingers crossed the issue is just air trapped in cooling system.

[Majorcnut]

A mechanic tested for combustion gases in coolant, came back negative.
I ended up buying the combustion gas test kit off Amazon and tested also, fluid did not change colour after letting gases bubble through the tester for over 3 minutes.
So I guess this is just air trapped in the cooling system, or air getting sucked into it somehow.

[Growlerbearnz]

That's a great sign. Hopefully it's just trapped air coming out and fitting a new tank will solve everything.