strange coolant leak

[ABrooks]

'94 D-90 (not mine, so bear with me) -- at idle but not with the motor off there's a severe coolant leak apparently coming from (of all places) the vent under the bellhousing on the tranny (auto conversion). So much of a leak that it's dumping half the cooling system within 5 miles. No clue how coolant would get into the bellhousing, but a tech at the dealer told the owner that there's some sort of valve between the block and the transmission that can stick open causing this. Makes no sense to me -- anyone have any thoughts?

TB

[PTSchram]

Look at the back of the intake manifold. It is not an uncommon failure, but sometimes very difficult to detect the source until the intake is removed, but then, it is immediately obvious.

This assumes you have checked heater hoses near the bulkhead.

[ABrooks]

Heater is bypassed. Thanks, I'll have him check the intake.

[Puffdragon]

you have probably blown the freeze plug on the back of the block. Not to uncommon. As for the tech telling you there was a valve between teh engine and tranny, What the hell. Don't ever take advice from that tech again. Any good mech would have been able to tell you you blew a freeze plug.

[ABrooks]

I guess $98 an hour doesn't get you much anymore (yes, that's how much the local dealer charges). I'm assuming that replacement is as nasty a job as it sounds like?

[Puffdragon]

just pull the tranny, pop out the old freeze plug, install a new one, pop the tranny back on, and your done. If you are properly equiped, count on 3-4 hrs. Its an easy job though. You will however want to replace the rear main, and clutch while your in there though.

[PTSchram]

KC:
Given the aluminum block, etc. is this a common failure mode? I suppose if one were to use an ionically active coolant, the galvanic action would be significant.

Edit-D'oh, I made the above comment thinking an iron block would be more likely to rust from the inside out, versus an aluminum block with steel (presumably) freezeplugs, and many warnings to regularly flush coolant and use "Clean" water.

I lost my first 4x4 to a broken crankshaft from overheating when a $0.26 freeze plug rusted out, and the ensuing mechanical carnage.

I guess I should have known what was going on here with the immediate loss of coolant, versus the elusive slow leak with an intake leak.

[Hanover Rover]

I had the same problem in a Disco, turns out it was the valley gasket leaking. The intake bolts had a tendency to stretch causing the gasket to let go of coolant but only whilst ticking over (heh heh) or when driving. I would check here before removing the tranny, it is after all alot less time consuming!! Good luck!

[Serious One]

Originally posted by Hanover Rover
I had the same problem in a Disco, turns out it was the valley gasket leaking. The intake bolts had a tendency to stretch causing the gasket to let go of coolant but only whilst ticking over (heh heh) or when driving. I would check here before removing the tranny, it is after all alot less time consuming!! Good luck!

Damn Hanover, for a newbie that's pretty good advice.

I can tell you haven't been tainted by D-Web because you know the proper spelling and application of the word 'tranny'.

Welcome! :flipoff2:

[Puffdragon]

He described the leak to be coming from the bellhousing vent, which menas the coolant could only be coming from teh freeze plug. Now if collant exist ontop of the bellhousing, the intake gasket would be suspect. Simply tightening the intake botls will not solve the problem permanently. A new gasket must be put in place. The gasket will loose its composite material over the course of time the more the truck leaks. If you are truely loosing coolant as fast as you say, the plug has poped. At rover, we generally repalce the rear plugs, and epoxy them in, to reduce the ability of them poping under normal operating conditions. It is not normal to pop the plugs after they have been replaced once. Generally, they stick better the second time around.

[Serious One]

KC, I was just saying that for a new-b that his grasp of the lingo, terms and apparent proficiency was impressive for someone with a post count of 2.

Weather or not he's right is TBD...:flipoff2:

[Puffdragon]

Nah Mike, he just sounds like he came over from chevy land or ford country. Most True AMERICANS :flipoff2: know what the proper terms are, and they dont get tainted by the backasswards lingo of those damn brits. Heehe:D

Just fawkin with you euro peep's I actually like the euro terms. It throws people some times.

Is it a stub axle, or a spindle That is the question.

Minor flame suite "ON"

Bring it on baby!

[Hanover Rover]

No disrespect Puffy but I was under the impression that in this forum one need not hold the hand of the original thread starter (since this is not D-Web). Of course you have to change the valley gasket, I never said you didn't and shame on me for assuming the folks at Pirate 4X4 could read between the lines. BTW I've never owned a Chevy but being that our beloved Rover V-8's are Buick engines what difference does it make? And when my valley gasket was leaking it appeared to be coming from the "vent on the tranny".

[PTSchram]

Originally posted by Puffdragon
The gasket will loose its composite material over the course of time the more the truck leaks.

It's a '94. More than likely, it has the steel intake/valley and 14 bolt steel head gaskets.

Either way, once the intake/valley begins to leak, it will worsen to the point where it will eventually leak into the crankcase, ultimately causing deterioration of the bearings and the carnage that ensues.

[Hanover Rover]

Whoops I meant the leak appeared to be coming from the bellhousing vent