Head Gasket or Water Pump?

arasb · **Posted:** Thu Mar 13, 2014 11:33 pm

I recently had my head gasket done because I had pressure in my coolant reservoir in the mornings as well as coolant in the overflow side of the reservoir. My coolant was clean and my oil wasn't milky, but I was loosing coolant and constantly had air in my upper large coolant hose. I also have been running with a failed (open) thermostat for over a year.

I took my rig to a semi-local place that had a reputable CRD mechanic listed here that has done a few heads. Upon tearing into the engine, I was told that my head wasn't leaking but my water pump was bad. They replaced the head, used ARP bolts, replaced my rockers, did the timing belt and pump as planned.

It seems interesting that a bad pump was causing pressure buildup and overflow. Can anyone shed some light as to how someone might be able to tell if the pump is bad vs the head other than a leak down? I'm glad I did my head with ARPs regardless, but wondering if there's an easy way to tell if it's just the pump.

Photos forthcoming...
Thanks,
Aras

arasb · **Posted:** Thu Mar 13, 2014 11:34 pm

flman · **Posted:** Fri Mar 14, 2014 7:23 am

If the pump had a leak on the intake side it can pull in air. Cylinder 1 & 2 was leaking, notice the rust?

papaindigo · **Posted:** Fri Mar 14, 2014 7:29 am

There have been reports that when the WP leaks coolant weeps out of the bottom of the TB inner cover which would be logical for a WP shaft seal leak. I have not looked at the KJ CRD WP but WPs I've seen in the past have a weep hole next to that shaft and you typically see a failed seal when with coolant drips out of that hole.

That said I don't see how, correct me if I'm wrong, a leaky WP could cause a coolant overpressure.

Maybe I'm imagining things but in picture #4 the staining on the left next to cylinders 1 and 2 sure looks like a leak to me.

Could be a leak there causing your coolant overpressure issue and an coincidental unrelated WP leak.

WWDiesel · **Posted:** Fri Mar 14, 2014 9:24 am

There is only one way over-pressure can happen in a cooling system on any water cooled motor, and that is by compression getting into the cooling system from a source. Those sources can be, a leaking head gasket (most common) or a cracked head (why they magaflux test heads for hairline cracks), or a cracked block (least common). The water pump cannot cause over-pressure, sorry, it is just not possible. Most water pumps only pump about 5 -7 psig at normal engine RPM's; not near enough to cause over-pressure.
Overheating can cause over-pressure when water flashes to steam. When this happens it will lift the safety over-pressure spring in the radiator cap and blow off... :wink:

I concur with the others; looks to me like your head gasket was leaking? :!:

arasb · **Posted:** Fri Mar 14, 2014 10:12 am

That completely makes sense. I was also told that my turbo is in great condition and was recently replaced (I've owned the vehicle from 30k to currently 94k and I certainly didn't replace it while I owned it), as you can see from my other post, my turbo is shot. :roll:

http://youtu.be/AnYNBs-FmYs
When I dropped off the rig, I was promised it back in a week. Over 4 weeks later, I got my jeep back (found quite a few loose or missing bolts in the engine bay, and they thoughtfully replaced my Fumoto drain valve with a standard drain bolt

). Needless to say I won't be going back there.

Thanks for your input.

WWDiesel · **Posted:** Fri Mar 14, 2014 12:51 pm

You stated: "reputable CRD mechanic". One might question this in light of what happened to you? :roll:

In your pictures, you can see where the top of no. 1 piston is washed clean, a sure sign of coolant getting into the combustion chamber. In a diesel engine, a piston should be covered in a light film of very dark carbon, not shinny and clean...
Best of luck. :SOMBRERO:

arasb · **Posted:** Fri Mar 14, 2014 2:16 pm

Thanks. I can't really say if the mechanic was the issue, but for sure the shop manager (who I had the only contact with) is an idiot (worst communication ever). I originally mentioned the 'steam cleaned' cylinder to the guy and he said it was cause of the flash on his camera. :roll:

thermorex · **Posted:** Fri Mar 14, 2014 5:33 pm

Geez, that makes me hate the "reputable mechanics" even more, lol. I only know 2 mechanics I could trust, only one with the crd, but they'll never get it to work at it due the shop Muppets they have around. I'd rather mess something up on my own learning than risk to whoop somebody's rear very hard...

Head Gasket or Water Pump?

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