Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Bumbazor]

Obviously the area of failure could give different symptoms, but would it be possible that the only symptom be coolant loss, of any amount and whether visibly detected or not?
Or, with hg failure causing coolant loss should I expect to see other symptoms?

I've checked everything else (hbv, cooler, bulkhead pipes etc) and just want a few more opinions before deciding what to do next.

Thanks

[TheBoy]

Could give lots of symptoms.  HG failure on V6 is very, very rare, except on 1998 3.0l, where visible coolant loss from rear of 2/4/6 bank is clearly visible.

[Bumbazor]

I know it's rare but I have just about exhausted all other causes, and I do suspect bad coolant maintenance, which of course doesn't help either.

[Abiton]

'Invisible' coolant loss will be associated with increased pressure in all the rubber hoses, if you have a leak that's getting into a cylinder.  Give the rad hoses a squeeze, if they feel like something your missus would enjoy, there's probably too much pressure in them.
 

[Ian_D]

Could give lots of symptoms.  HG failure on V6 is very, very rare, except on 1998 3.0l, where visible coolant loss from rear of 2/4/6 bank is clearly visible.

Makes me cringe every time I read that  :-/ ...

Tick ... tock... tick... 




<--- Its a 1998 

[Bumbazor]

'Invisible' coolant loss will be associated with increased pressure in all the rubber hoses, if you have a leak that's getting into a cylinder.  Give the rad hoses a squeeze, if they feel like something your missus would enjoy, there's probably too much pressure in them.
 

The trouble is I've got most of the bits off the engine apart from cams and heads, and the coolant is drained so I can't check this now.

[Abiton]

In that case, bright torch shone down the sparkplug holes should show you whether there's been any coolant going into any cylinders.  Should look nice and dry on the piston crowns unless there was any oil around the plugs before removal.

[dbug]

This may help - 1998 2.5 Elite Estate - coolant loss.  HBV leaking, replaced genuine Vx - now dry.  Still some coolant loss - water pump seeping and bearings a bit noisy - replaced.  Journey of 280 miles followed by one of 140 miles in 2 days - all ok and no water loss.  Then water loss again up to 1 lit over 25 miles.  Appears to be from rear passenger side of block - not dreaded HG or could it be from the vee - coolant bridge/oil cooler plate.  Oil cooler was replaced about 5K miles ago - all new coolant bridge seals and plate resealed ok.

Get a second pair of eyes!! What appeared to be leaking from rear nearside corner of engine wasn't - not coming down bell housing but along chassis rail.  Actual leak was from slight hole in bottom of top hose where it goes into block.  Moral get a second pair of eyes!!

Saved me stripping out plenum/inlet manifolds to check oil cooler plate etc.  New top hose going on tomorrow  


HTH

[Bumbazor]

dbug your symptoms and actions are uncannily similar, if not a gnat's whisker away from exactly, my situation.
Had a leaking hbv; replaced.
Water pump replaced about a year ago during cambelt change.
Sometimes no loss, sometimes a lot over short journey.
Replaced oil cooler.

Now for the question; this top hose you mention, is it at the front of the engine, about 40mm diameter?

[dbug]

Hose runs from top of rad (nearside) to block (just next to abs ecu) on nearside of block.  Original hoses were not strengthened on the "corner" about ½" from clip (new are  ).  Mine is leaking through small hole underneath hose - can only be seen from under car.

Part nş is 9240144 - £12.10 on TC 

[Bumbazor]

Interesting; I removed that hose and noticed it had a strengthened corner. Anyway, it's easy for me to check now (well, tomorrow).

[Darth Loo-knee]

Another thought is the thermostat, oil cooler plate or dowty washer on the coolant bridge.... do you smell water/anti freeze even when you can't see the leak? it could be evapourating with the heat down there.

My suggestion would be to pressurise the water system with the inlet manifold off keeping a sharp eye out for any leaks... I saw a tear drop leak coming out of the dowty washers on the coolant bridge on one car :-?

[dbug]

Another thought is the thermostat, oil cooler plate or dowty washer on the coolant bridge.... do you smell water/anti freeze even when you can't see the leak? it could be evapourating with the heat down there.

My suggestion would be to pressurise the water system with the inlet manifold off keeping a sharp eye out for any leaks... I saw a tear drop leak coming out of the dowty washers on the coolant bridge on one car :-?

Convinced my leak was from that area - even got some new dowty washers.  Now got to replace holed top hose.

[Bumbazor]

I've done the pressure test with all the plenum etc off but couldn't see (or smell) anything. I suppose it's worth replacing the washers and resealing just in case.