Coolant leak / water pump questions

[berickson926]

I used a loaner pressure tester to do a 15psi check and bleeding of the system. System slowly loses pressure over time.

After several rounds of bleeding I finally noticed a coolant leak coming off the bottom of the water pump, drivers side.


I've had overheating issues in the past and have still been trying to sort everything out. Things I've done so far:

Replaced radiator (and the flexible hoses immediately connecting to it)
Replaced otterstat
Replaced fan/fan fail relays with bitsyncmaster's upgrades.
Replaced fan CB and repaired corroded wire connection to CB.
Had DMC CA replace all the flexible coolant hoses under the intake.
Installed the auto bleeder kit.

System generally does a poor job cooling itself - just idling it can take 3-4 minutes or more for the car to cool down enough for fans to turn off. Maybe that is okay? I'm not really sure. It can still run hot when driven in reverse or while navigating parking spots in a parking lot.

I was still trying to figure out how air was getting into the system (worried about head gasket failure, to be honest) aside from me doing a poor job bleeding the car. Then I finally noticed this leak under the water pump.


I've also read there is a weep hole that can leak, but not really sure what solution there is when this happens. Am I looking at a water pump replacement?



I took a few pictures looking down on the engine but they aren't too useful. I will go back underneath the car to see if I can get a better shot.

[DMC-81]

Hi there,

My understanding is that if the water pump leaks through that weep hole, it has or is beginning to fail.

Best of luck with your diagnosis and repair. I am in the middle of an engine refresh including a pump replacement, and this forum and a workshop manual are valuable.

[Jonathan]

System generally does a poor job cooling itself - just idling it can take 3-4 minutes or more for the car to cool down enough for fans to turn off. Maybe that is okay? I'm not really sure. It can still run hot when driven in reverse or while navigating parking spots in a parking lot.

Believe it or not, the system does cool the car well, but your example has the logic for why a bit backwards. The car's cooling system will keep the car cool enough often without the fans running when you are out cruising around at highway speeds. Depending on the ambient temperature that day for where you are of course. The air flow of the car moving and going in the front and past the coolant going through the radiator is often sufficient. It can have a harder time staying cool or longer fan running duration, as you noted, when sitting idle. Not because of high RPMs creating more heat, but because at the low RPMs when idling, you aren't moving. You follow?


I used a loaner pressure tester to do a 15psi check and bleeding of the system. System slowly loses pressure over time.

After several rounds of bleeding I finally noticed a coolant leak coming off the bottom of the water pump, drivers side.

I've had overheating issues in the past and have still been trying to sort everything out. Things I've done so far:

Replaced radiator (and the flexible hoses immediately connecting to it)
Replaced otterstat
Replaced fan/fan fail relays with bitsyncmaster's upgrades.
Replaced fan CB and repaired corroded wire connection to CB.
Had DMC CA replace all the flexible coolant hoses under the intake.
Installed the auto bleeder kit.

I was still trying to figure out how air was getting into the system (worried about head gasket failure, to be honest) aside from me doing a poor job bleeding the car. Then I finally noticed this leak under the water pump.

I've also read there is a weep hole that can leak, but not really sure what solution there is when this happens. Am I looking at a water pump replacement?

You list most of the main things to go wrong or need replacing. You might have been fighting more than one cause, or you might have replaced more than the thing that was causing the problem.

I can't tell you much about water pump replacements or weep holes as I haven't replaced mine, but once you get that sorted out, go back to basics and make sure the air is bled out first and then ensure the fans are coming on via otterstat jumper and/or A/C clutch engaged. Confirm the fans are blowing a decent amount of air and making lots of noise and then continue with troubleshooting. No air in the system and fans coming on when they should will generally solve the majority of problems.

[berickson926]

Thanks for the feedback!

Here are some pictures, but it is still a little hard to see.

33956339573395833959

[DMC-81]

I'd verify the exact location of the leak. Is it coming from the weep hole, or from below the pump (from the engine valley). As you stated, you had some hoses replaced under the intake, so you will want to ensure those hoses are not leaking from a loose clamp. Do you know how old your pump is?

[berickson926]

Unfortunately I don't know how old the pump is, and have only owned this car for about a little less than a year.

I'm not really sure how to get in there for a better picture without taking the intake off.

I'm also not even really sure what this weep hole looks like, most diagrams don't seem to show the pump from the back/bottom.

[SS Spoiler]

DMC 81 is right....I ended up replacing a pump when all it was a loose clamp....grrrr

[kings1527]

An outstanding recommendation from Dave Swingle in a different thread:

-Try jacking your car from the front and seeing if the leak becomes greater when you lift the car and tilt it back towards the water pump. If you get an immediate flow from doing that, then you have coolant in the valley and very possibly have a clamp/hose issue under the manifold. If the leak doesn't get worse when you lift the car, it's something else.-

[DMC-81]

Here's a picture of a new and an old water pump bottom. I have pointed to the hole with a pen....

33962

[David T]

If you go under the car and look up at the nose of the water pump (behind the pulley) you will see the weep hole. If you see moisture or even just staining, it is leaking and it should not leak at all. To replace the water pump the intake manifold has to come off again. Bottom line, if you have ANY leaks eventually you will lose enough coolant so that air will get into the system and once that happens the car will overheat.

[berickson926]

Thank you again for the feedback, everyone!

With the engine cold but pressurized to 15psi, the leak was back. I felt around for the weep hole and it was dry.

What little I can see of the valley with a flashlight looks dry, except somewhere right under the connection between the pump and the y-pipe. This coincides with coolant leaking off the block to the left/drivers side of the water pump.

My suspects are items 8/10 going off of this diagram (http://store.delorean.com/c-270-1-3-0-water-pump.aspx).


I've been reading various resources on the intake removal procedure, and while I'm still pretty intimidated by this task I'm willing to give it a try. It seems unavoidable at this point.


I have no idea when the PO changed the spark plugs last, and the WUR is supposedly clogged. Might be a good time to tackle a few other things!

[kings1527]

Thank you again for the feedback, everyone!

With the engine cold but pressurized to 15psi, the leak was back. I felt around for the weep hole and it was dry.

What little I can see of the valley with a flashlight looks dry, except somewhere right under the connection between the pump and the y-pipe. This coincides with coolant leaking off the block to the left/drivers side of the water pump.

My suspects are items 8/10 going off of this diagram (http://store.delorean.com/c-270-1-3-0-water-pump.aspx).


I've been reading various resources on the intake removal procedure, and while I'm still pretty intimidated by this task I'm willing to give it a try. It seems unavoidable at this point.


I have no idea when the PO changed the spark plugs last, and the WUR is supposedly clogged. Might be a good time to tackle a few other things!

Very common. In fact, that's what I have going on right now. If I pressure test my system, it'll bleed down slowly but I don't see any leaks. I'm guessing it's going into the valley although my coolant level stays pretty good. I did a water pump replacement along with changing all of the hoses you referenced to silicone. They packed down a little bit but now I need to get back in there and re-tighten them.

Taking the manifold off is a very easy thing to do and the best thing you can do to help yourself is to just do it and gain the experience. When you get comfortable and confident with taking it off, the job becomes relatively quick but easy. Just be sure to photograph everything along the way and bag all of the parts and label them as you go. That'll make reassembly MUCH easier. Any anytime you have the ability to place bolts back in the threads to hold them there until reassembly, do it.

I'll re-tighten my stuff when I take it off but I'll also do a cap and rotor, plugs, replace the hot water valve, and replace some coolant hoses on the underbody of the car which I believe to be original. Those have to go ASAP. Other things to consider would be a valley deep cleaning, get the injectors flow tested and cleaned, and replace the clutch slave.