Replacement Water Pump Longevity

[kings1527]

After about 3 years and 14k miles, it looks like my DMCH replacement water pump may be leaking. I found some residue on the timing chain cover right in-line with the water pump weep hole that looks like evaporated coolant. I can't say for certain and I'll have to monitor it so I can pick it up when it's fresh, but I'm 90% sure that's what I'm looking at. It's your typical residue pattern with such a problem.

Installation went fine back then and I can't think of what could've gone wrong to shorten the lifespan but I feel that that's definitely fast wear. I live in a hotter climate and my engine temp regularly sees 220-225 constant while driving around with the AC during the summer months. Not sure if that has any effect with the bearings. I'm not noticing any wobble or abnormal noise and if it is leaking, it's a small amount (so far).

What's been the average life expectancy with the replacement water pumps?

Thanks.

[DMCMW Dave]

I don't recall seeing any in-service failures of replacement pumps on customer cars (other than Holler's pump shaft snapping off at maybe 100K miles). I replaced the pump for the second time on my personal car in 2015, it was probably from about 1999 but maybe 20,000 miles. I don't even recall which vendor it came from at the time, but I'm sure they all came from the same factory anyway. Seems like low miles but 15 years is pretty good in my book.

Keep an eye on it, the occasional drip/green dust residue is not failure, sometimes a bit will just sneak past the seal.

I'd call it unusual but stuff happens.

[kings1527]

I don't recall seeing any in-service failures of replacement pumps on customer cars (other than Holler's pump shaft snapping off at maybe 100K miles). I replaced the pump for the second time on my personal car in 2015, it was probably from about 1999 but maybe 20,000 miles. I don't even recall which vendor it came from at the time, but I'm sure they all came from the same factory anyway. Seems like low miles but 15 years is pretty good in my book.

Keep an eye on it, the occasional drip/green dust residue is not failure, sometimes a bit will just sneak past the seal.

I'd call it unusual but stuff happens.

Great info. Thanks a bunch, Dave.

[David T]

Great info. Thanks a bunch, Dave.


Things that can contribute to water pump failure:
Old coolant
Not using a 50/50 mix of coolant with a water pump lubricant (most have them already mixed in)
Hard water
Too tight a belt
Dropping a pump before or during install
Long periods of inactivity
A lot of solids floating around in the coolant like sand which would damage the seal
Running the pump without coolant

Like Dave says, a small amount of weepage can be considered "normal". If you are worried do a pressure test.

[sdg3205]

One of your hose clamps is probably loose. I've had this too, and it is always the LH or RH elbow hose from the pump to the block, where one hose clamp has loosened. Next time, I'm using silicone hoses.

[kings1527]

One of your hose clamps is probably loose. I've had this too, and it is always the LH or RH elbow hose from the pump to the block, where one hose clamp has loosened. Next time, I'm using silicone hoses.

Thanks, guys. Yeah, I thought about that but I already have silicone hoses on the car (which actually DO pack down a little bit when new) and I tightened them up the last time I had the manifold off for some different work. I doubt that's it but I'll keep it in mind as I'm trying to pinpoint this thing. I'm feeling better about hearing that some seepage could be considered normal. It was definitely a small amount (i.e. never noticed any coolant on the ground) but worthy of tracking.

[louielouie2000]

When I bought my second DeLorean in 2003, it came with a replacement Volvo-style water pump. Within a year of my purchasing the car, the pump started weeping. I'm not sure how old the pump was, but the previous owner told me it had been replaced during his watch. That car was a higher mileage DeLorean, too- it was used as a daily driver by several prior owners and had something like 75,000 indicated miles at the time. I suspect the actual mileage was much higher, and that I likely installed the 4th water pump on that car. So replacement pumps definitely go out on DeLoreans. When the pumps weep they leave a pretty distinctive spray pattern beneath them.

Regarding why DeLorean pumps seem to have a short life in DeLoreans, I still go back to my heat theory. The pump only sits a few inches away from the muffler, which was certainly not something the PRV was engineered to account for. Most DeLoreans also have a dark stripe down the middle of their mufflers, too- this is from heat, it's the hottest part of the muffler; which lines up exactly with the location of the water pump. Not only that, many DeLoreans original asbestos heat shields disintegrated over the years, leaving the pump with little heat protection. Further, I am still highly suspect of the early stainless replacement heat shields some DeLoreans are running around with. Aluminum reflects heat something like 7 times more effectively than stainless, which is why pretty much every modern engine has multiple aluminum heat shields strewn across their engine compartments. Stainless on the other hand tends to absorb and radiate heat. Combine that with the fact that most DeLoreans see extreme and erratic temperature variations due to the fact they aren't driven often, and I think all of this paints a picture telling us why water pumps don't tend to last too long on these cars.

Also, this was discussed in another thread recently, but apparently it is indeed possible to swap out the water pump without removing the intake. I found this method on several websites; looks like you just have to remove the thermostat:

https://www.volvoclub.org.uk/faq/EngineV6.html

[Ryan King]

Whatever you do, DON'T buy a pump with a 'Re-Pressed" on pulley. I did from a vendor, pulley backed off and caused me a ton of trouble.

I ended up buying a new pump from RockAuto for a Bolt On Pulley attachment. Now I run a bolt on Pulley. Gives me more leverage too when finding a replacement pump with a bolt on pulley. And in case I have to do one on the road (Extreme Circumstances), I wouldn't need to find another place to press it on etc.

Pulley backed off of this pump. You can kinda see around the shaft the gap. Pulley looked to be brand new, and said "OK" on the inside written in marker. But after 1 day or so of use the pulley backed off the pump.
460774607946080

New Pump and Pulley. Best way to go, IMO, for part availability and reliability.
46078

[DMCMW Dave]

Whatever you do, DON'T buy a pump with a 'Re-Pressed" on pulley. I did from a vendor, pulley backed off and caused me a ton of trouble.

New Pump and Pulley. Best way to go, IMO, for part availability and reliability.
]

Agreed, although at this point I believe non of the major vendors are recycling pulleys. They are either new steel pulleys (DMCH companies) or new aluminum pulleys (Grady, last time I saw one). Not sure about the others.

[DMCMW Dave]

Thanks, guys. Yeah, I thought about that but I already have silicone hoses on the car (which actually DO pack down a little bit when new) and I tightened them up the last time I had the manifold off for some different work. I doubt that's it but I'll keep it in mind as I'm trying to pinpoint this thing. I'm feeling better about hearing that some seepage could be considered normal. It was definitely a small amount (i.e. never noticed any coolant on the ground) but worthy of tracking.

This is going to go against the grain but I've seen more leaking problems with silicone hoses than with rubber hoses. No idea why, they are *supposed* to be better.