Need some guidance from you water-cooled experts. I’ve 20 years on Aircooled T1 and T2, but still pretty new to my 1990 T3.
1.6TD JX Karmann Gipsy, 2.6t unladen, she’s a big old unit.
Long story short, my coolant is foaming:
This is a small sample of the foam that escaped when I loosened the dalek cap slightly, it's not come from the sensor thread, which is coolant- tight. The foam bubbles look clean and soap-like, like a lather, as if washing-up liquid had been added to the coolant
Background
Few months ago, as preventative maintenance, cooling system incl radiator, was flushed with water. Radiator tested with boiling water, no cold spots. Fresh 50/50 coolant mix added, system bled, ran fine through to end of summer. All good.
About month ago noticed coolant level was dropping slightly. No obvious leaks, so added K-Seal and topped up coolant. Not driven much since.
Driving home from work recently, weather freezing cold, cab heating all good. After 30 mins hard drive, fortunately only ¼ mile from home, blower started belting out cold air, lost all heating, and coolant light came on.
Started diagnosis the following morning:
- Overflow tank (that behind reg plate) has obviously vented as there was copper-coloured K-Seal residue on its exterior. Its coolant level had since fallen back to below the min level mark, but wasn't empty.
- Header tank level down about ½ inch from top (I previously filled it to the brim under hard revs)
- Started her up, idled & revved until temp gauge just started to pass the cool-engine zone. No issues.
- Observed lot of activity in header tank, looked like a mini Niagra Falls in there. Carefully loosened dalek cap and white foam started escaping. Gently removed cap and lot more foam was expelled, more revs = more foam. Like a bottle of Radox in a deep bath !
- Kept replenishing header with 50/50 coolant until no more foaming.
- Replaced dalek cap, weather too cold so came in.
- Stone cold engine. Removed dalek cap, very light amount of foam atop of healthy-looking pink coolant:
- Bought up to temp, no warning light, revved and bled at the radiator for good measure. Went for hard 20 mile drive, incl. moderate hill, no issues at all, cab heating was brilliant. Gauge didn’t even reach centre-point, tho very cold weather.
- On return, placed cardboard under front and back of van, didn’t capture any coolant leaks.
- Slowly eased of the dalek cap, more foam and octopus hose very hard.
- Turned engine off. Lot of noise from the header tank, sounded kinda like a kettle gently boiling. Didn’t subside completely for a good ten mins. This could be normal, but I’ve just never noticed it before. Hopefully this vid emphasises such : [url]https://youtu.be/CNmNa1fOCgE[/url]
So….. is this likely a side-effect from adding K-Seal ? Googling suggests this is a possibility, albeit rare, and that the foaming should subside overtime.
Or something more sinister…i.e., head gasket going/gone ? If so, I;ve got my tools at the ready..
Cheers,
Gareth.
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