Sporatic engine noise / cooling issue .. Any help would be great!

Hi there,

I have a 1981 model and have been having an issue on and off for a couple of years that I believe is just getting worse.

Over the past couple of years something manages to rip off the water pump belt while driving. For the one time where I actually managed to find the belt on the road, it looked as it was ripped apart / slightly melted. I have been ordering replacement belts from delorean.com to make sure I am using the correct ones.

I will tell you that before each of the incidents I would notice that my car would make a loud sporadic noise coming from the engine compartment while driving (there is no way to actually replicate the issue, it just happens randomly while driving). It almost sounds as a grinding noise, and when this noise happens, I notice that my temperate gauge will increase up to high levels, then drop back down to normal levels.

Now I am having the issue again and would like to try and resolve it before loosing another water pump belt, or something more serious happens. A part of me thinks that something is seizing up the pulley system for the water pump it's just odd it just happens at the most random times and then will free itself up...(However eventually, I will loose the belt it's just a matter of time). If that is the case, what should I look into replacing, or inspecting?

To begin my troubleshooting I went ahead and followed a guide on this forum and did a coolant flush, installed new coolant.

****I will also note that I have been leaking coolant for some time as well, looks to be around the head gasket , but not exactly sure (the head gaskets were replaced at the DMC dealership in FL 3 years ago along with 20K of other work), you can also see coolant dripping out of the overflow pipe coming out of the coolant bottle.

Would appreciate any help. I drive my car pretty regularly, and to be quite honest this is the only main issue that i've had with my car, since I purchased it 3 years ago. I am sitting at 52K miles.

Thank you!

For the belt to fly off the common causes are:
Pulleys out of alignment
The bearings on either the alternator or the water pump are bad
The belt is put on WAY too tight
The belt gets damaged putting it on
The belt is defective

My bet is on the 1st or 2nd causes. Get under the car and look up at the weep hole on the neck of the water pump. If you see any staining or wetness replace the water pump. Look at the belt and the pulleys. Does it look like it is in line?

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Originally Posted by David T

For the belt to fly off the common causes are:
Pulleys out of alignment
The bearings on either the alternator or the water pump are bad
The belt is put on WAY too tight
The belt gets damaged putting it on
The belt is defective

My bet is on the 1st or 2nd causes. Get under the car and look up at the weep hole on the neck of the water pump. If you see any staining or wetness replace the water pump. Look at the belt and the pulleys. Does it look like it is in line?

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Thanks for the quick reply!

As far as the bearing on the water pump, is this repairable, or would I need to just replace the entire water pump, or would I be fine just getting a new water pump pulley? I installed a new Alternator about 4 months ago. I checked the belts, and they are in good shape, I purchased them from delorean.com.

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Originally Posted by Chrisjohnsona4

Thanks for the quick reply!

As far as the bearing on the water pump, is this repairable, or would I need to just replace the entire water pump, or would I be fine just getting a new water pump pulley? I installed a new Alternator about 4 months ago. I checked the belts, and they are in good shape, I purchased them from delorean.com.

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If the seal and/or the bearings are bad on the water pump you replace the water pump. Did the belts start falling off AFTER you did the alternator or before?

I'd bet your water pump is failing. I had an issue a long time ago where it seemed the pump shaft would move in/out causing the impeller to hit the back plate. I got a grinding noise and a belt popped of and was laying on my exhaust. I was lucky to be close to home and I made it there without the belt and without overheating! Once I disassembled the pump I could see that the impeller had hit the plate. The pump was a replacement from a vendor notorious for cheaper parts and I do not purchase from there anymore so you are wise to stick with DMCH or other reputable vendors like Grady.

Also check the condition of your overflow tank cap, if the rubber seals are brittle or cracked it is time to replace!

You mention DMCFL did some work, are you located in Florida?

If you have some coolant leaking in the engine compartment, it wouldn't take much for it to land on the water pump belt. Coolant is very slippery and even a few drops on the belt would cause it to spin on any of the pulleys, over heat and crack. I wouldn't even be driving a D that has coolant coming out of the head gasket if the compression in the cylinder is causing the coolant to push out you are also cutting into the head/block. Do a compression test and see which cylinder is leaking the coolant. Do a radiator/ cooling system pressure test see if it will hold. I think the broken alternator belts are the least of your problems. :race:

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Originally Posted by cdrusn

If you have some coolant leaking in the engine compartment, it wouldn't take much for it to land on the water pump belt. Coolant is very slippery and even a few drops on the belt would cause it to spin on any of the pulleys, over heat and crack. I wouldn't even be driving a D that has coolant coming out of the head gasket if the compression in the cylinder is causing the coolant to push out you are also cutting into the head/block. Do a compression test and see which cylinder is leaking the coolant. Do a radiator/ cooling system pressure test see if it will hold. I think the broken alternator belts are the least of your problems. :race:

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According to the invoice records I have for all the work that was done on this DeLorean in FL, the head gaskets were replaced, among various other engine work. Perhaps its the same Water Pump however from when the car was manufactured.

I'm going to spend some time further inspecting the belts.. They were purchased from DMC recently and replaced. Perhaps maybe tightened too much, however I haven't ever had any squealing noises, etc. It is odd that I am getting this engine noise right after I did a full coolant flush. I did do a radiator / cooling system pressure test and it does hold solid.

The car has overheated a couple times due to the water pump belt coming off without me knowing, up until the point where I see smoke coming from my engine compartment. Never a fire, just coolant dumps out of the overflow hose on the coolant bottle. The Cap was replaced when all the work was done, and seems to be holding pressure well.

Sorry for all the comments / questions, but finally.. I did want to ask again.. If after inspecting the water pump and it seems to be in normal working condition , has anyone ever just changed the pulleys (bearings) themselves? I see they sell them individually on the DeLorean site.

I'll do a compression test at this point and see which cylinder is leaking. From just looking at it, I can tell you it's coming from the right side of the engine (facing the rear of the car).

Thanks for all of the feedback so far, would love to not run into further more expensive issues by what I am experiencing currently. I drive the car pretty regularly.

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Originally Posted by Chrisjohnsona4

Sorry for all the comments / questions, but finally.. I did want to ask again.. If after inspecting the water pump and it seems to be in normal working condition , has anyone ever just changed the pulleys (bearings) themselves? I see they sell them individually on the DeLorean site.

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How did you inspect the pump? Because the noise you are describing sounds exactly like the noise I started hearing back in June, and after taking the belts off I was treated to this;

https://www.youtube.com/watch?v=OvBPNPeEj8E

You can replace the bearing in the pump as there are folks in the UK who refurbish these pumps, but my understanding is that it's a pain of a job for a DIY'er without sources for the right bellows and seals. There is a thread on the Eurotec forums about it with some details, but it sounds to me like it might be outside your comfort zone. Replacing the pulley alone won't do you any good as the bearing is not on the pulley but between the pulley shaft and the pump body.

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Originally Posted by jwrayth

How did you inspect the pump? Because the noise you are describing sounds exactly like the noise I started hearing back in June, and after taking the belts off I was treated to this;

https://www.youtube.com/watch?v=OvBPNPeEj8E

You can replace the bearing in the pump as there are folks in the UK who refurbish these pumps, but my understanding is that it's a pain of a job for a DIY'er without sources for the right bellows and seals. There is a thread on the Eurotec forums about it with some details, but it sounds to me like it might be outside your comfort zone. Replacing the pulley alone won't do you any good as the bearing is not on the pulley but between the pulley shaft and the pump body.

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Thanks for the great info!.. So changing out just the entire water pump resolved your issue? If thats the case and you purchased a new water pump, where did you source yours from, Delorean.com or Grady? Or another? Any DIY for changing the Water Pump?

Also did you experience the random noises like I was describing, which lead to sporadic overheating and belt's flying off?

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Originally Posted by DeloreanChris

Thanks for the great info!.. So changing out just the entire water pump resolved your issue? If thats the case and you purchased a new water pump, where did you source yours from, Delorean.com or Grady? Or another? Any DIY for changing the Water Pump?

Also did you experience the random noises like I was describing, which lead to sporadic overheating and belt's flying off?

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I haven't actually had the opportunity to change my pump yet due to life getting in the way, but from the way you describe the noises that fits almost exactly with what mine sounded like last I was driving her. She didn't throw belts or overheat, but the belt was visibly wobbly with the motor running. I only had to make a journey of 30 miles the last time I drove it and timed it for when there was minimal traffic.

The replacement pump I have to fit is a Skandix one with a bolt-on pulley rather than the press-on type. I opted to go for this over a DMC/DMC.EU version due to mixed reports on quality, where as the Volvo community had nothing but good things to say about the Skandix pump. I intend to get my current pump refurbished once I have it off the car so I have a spare.

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Originally Posted by jwrayth

I haven't actually had the opportunity to change my pump yet due to life getting in the way, but from the way you describe the noises that fits almost exactly with what mine sounded like last I was driving her. She didn't throw belts or overheat, but the belt was visibly wobbly with the motor running. I only had to make a journey of 30 miles the last time I drove it and timed it for when there was minimal traffic.

The replacement pump I have to fit is a Skandix one with a bolt-on pulley rather than the press-on type. I opted to go for this over a DMC/DMC.EU version due to mixed reports on quality, where as the Volvo community had nothing but good things to say about the Skandix pump. I intend to get my current pump refurbished once I have it off the car so I have a spare.

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Yeah, I checked mine last night with no noticeable movement in the pump itself, very, very odd. It's like a grinding noise that lasts for like a second and goes away. It's more noticeable now since I did my last coolant flush.Perhaps the compression is off, or something.. haven't got a chance to check that yet.