StratfordShark

Recently I opened garage door to see a very small (size of quarter) droplet of coolant, with a 'snail trail' leading to underneath oil pan (the undertrays are currently off while I finish some jobs).

Searching posts here I've seen worrying references to water pump leaks!

The pump was replaced with a new one by a guy with highest reputation for working on 928s when he installed new timing belt. That was 2200 miles ago (yes I plan to do the re-tension this week!). I know that pumps can fail even when new.

Since spotting the coolant I've done a couple more trips, left car in garage and seen no more coolant collecting underneath.

I've just shone a torch onto top of oil pan and can see several drops/pools of coolant (but not enough to have dripped onto floor). With engine idling I couldn't see anything dripping onto that area.

I don't know if it's relevant that shortly before the first 'spill', I had overfilled the coolant reservoir a couple of inches above seam. It's now exactly on the seam. Could excess coolant be blown out onto the oil pan?

Before I talk to the guy who installed the pump, what's the best way of checking for a water pump leak? I will be removing rhs cambelt cover this week to do re-tension - will a water pump leak be obvious with this cover off or do I have to remove more bits to know for sure?

Thanks,

Adrian

AO

With an 88 you cannot run the engine with the covers off. Your best bet is to pressurize the coolant system via the reservoir tank. Then wait and watch. You may have a coolant leak from the the coolant crossover or thermostat which are in similar locations. Could also be one of the multitude of hoses that connect up there. My bet is on one of the hoses. You might just try snugging (don't go crazy) up all the hose clamps and see if that takes care of it.

Edit: If you do not have access to a tool to pressurize the coolant system, just get the engine hot (20 minute drive) and then park it. With the engine running rev the engine by hand and watch the hoses. I had a hose that would only leak under load.

Bill Ball

A couple of inches over the seam is not going to overflow. In fact, the correct height is a bit above the seam. If the cold level is falling, you have a leak worth investigating. A proper system will not lose any measurable coolant.

Can you find a trail of coolant on the front of the motor or a puddle on the front upper surface of the oil pan? Did it drip off the front, rear or one side of the motor/oil pan?

Most likely source is a slightly loose coolant hose. Check the seating and clamp tightness of the small as well as large hoses.

New water pumps can bleed a little out the pump breather hole, but it shouldn't reach the floor.

StratfordShark

Thanks Andrew - great tip on revving by hand and watching.

I replaced coolant bridge o-ring and gaskets a few months ago. I didn't see any coolant in the 'wells' of the bridge which is where I had a small leak before I replaced rubber there.

Will do your test before I tighten hose clamps so that I'll know for certain if hose is the source.

StratfordShark

Hi Bill,

There are a few puddles on front upper surface of oil pan. Can't find a trail.

The forensic evidence for original small pool of coolant under car is now gone, so I can't be certain exactly what area of the pan the coolant came off. From memory of looking under car when I first found leak, I would say front of pan.

Thanks for your expertise.

StratfordShark

I think I found it. Just went out to double-check coolant bridge. There is a pool of coolant in the well on RHS which I'm guessing/hoping has dripped down from the connection of hose from coolant reservoir, or possibly the top hose.

I'll check it further when it's hot.

PorKen

<<< You can run a 32V with the center cover off, don'tchaknow.

Mrmerlin

but first you must have the A/C pulley removed to remove the front cover, that means removing the crank bolt

AO

Yes, I knew some wise-*** was going to point that out... Thanks Ken!

PorKen

It's not pretty, but you can twist and walk the cover around the A/C pulley, one side at a time. BTDT.