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Topic: ISM450 coolant leak near pump (Read 890 times) previous topic - next topic

ISM450 coolant leak near pump

Hi everyone,
Yesterday I decided to snug this bolt up, first pic,which has developed some discoloration. I used a 3/8" ratchet and it snugged up just a hair.

I took the coach out for an 80 mile run and when we got back checked for leaks from the radiator but found nothing. We get drips every once in a while from the radiator.

This morning, with a low of 23 last night, I got under the coach to find the hydraulic pump # and I had a puddle of radiator fluid under the coach dripping once every 10 seconds. It seems to be coming from above water pump? Not sure.

I hope these pics help.
Trying to find a bolt to tighten.

Re: ISM450 coolant leak near pump

Reply #1 –
Try getting some brake cleaner and spray the wet spots until dry,then watch as the leak appears,as the engine cools from
running temp. the leak will get worse.Maybe get some new clamps for future use,those don't look that bad but look borderline.

Re: ISM450 coolant leak near pump

Reply #2 –
Thanks John,
Engine temp this morning was 39. I turned on the engine heater on the Aquahot and is currently at 66. Dripping has significantly slowed down  if not stopped.
I'll clean as you advised and look for new torque clamps.

Re: ISM450 coolant leak near pump

Reply #3 –
There is a large oring between the two that after 22 years dries up and starts leaking. Got to remove alternator and a bunch of stuff to get to it and I would recommend replacing the associated hose at the same time. Will need to drain coolant below level to open up system

Re: ISM450 coolant leak near pump

Reply #4 –
to add to Scotts post there is a oil cooler that is forward of the water pump you will also want to pull it and change gaskets and o-rings while you are in there.  When mine did this I decided to go ahead and change the water pump since it was 20+ years old.
I visited with mike on this forum (Pamela & Mike) and went with a NAPA water pump about half the price of cummins and they have stores nation wide. Mike suggested changing gaskets on oil cooler.  If it starts leaking later then you would have to take the world back apart to get to it.
Just my take
Chris 

Re: ISM450 coolant leak near pump

Reply #5 –
Quote from: Chris m lang –
to add to Scotts post there is a oil cooler that is forward of the water pump you will also want to pull it and change gaskets and o-rings while you are in there.  When mine did this I decided to go ahead and change the water pump since it was 20+ years old.
I visited with mike on this forum (Pamela & Mike) and went with a NAPA water pump about half the price of cummins and they have stores nation wide. Mike suggested changing gaskets on oil cooler.  If it starts leaking later then you would have to take the world back apart to get to it.
Just my take
Chris
That is great additional information. On my ISB the non Cummins pumps don't last as long or cost near as much, but I think if I was in there that deep a couple hundred more for a OEM pump would offset never worrying about it in my life. Just my $200.02 opinion
Genuine OEM Cummins ISM QSM L10 M11, 11 Liter Water Pump Kit 4955708 4089389...

Re: ISM450 coolant leak near pump

Reply #6 –
Thanks Scott, I think this is a pic of the o ring.

Re: ISM450 coolant leak near pump

Reply #7 –
Chris, I'll look for the oil cooler forward of the water pump.

Re: ISM450 coolant leak near pump

Reply #8 –
Cummins QuickServe Online

Put in your serial number and get the correct part

Re: ISM450 coolant leak near pump

Reply #9 –
I am having a similar leak as pictured at the top of this thread.  Thought it was the top of the hose but the leak is higher and likely from the pump to block interface.

I find the Cummins online parts system confusing to say the least.  They do not have a detailed parts exploded view so you are just guessing on the part you need.  From the online details that I found, you could have the o ring selection of part numbers: 3818885, 3037537, or 3046943.  From the post that shows a service manual diagram, I think I see the o ring but no details are shown on the Cummins site to make a selection to the correct o ring.

I better choice is to take it apart and bring the o ring to NAPA and select a appropriate one.  As for the gasket,  gasket material and RTV make for a speedy fix without getting the wrong ordered parts.

Good luck with the fix.

Re: ISM450 coolant leak near pump

Reply #10 –
Think on the o-rings I would order all 3 ,can't be that much and you will get the right one or find a Cummins store that knows how to order parts,another option is to find a actual parts book,check on Ebay.
 

Re: ISM450 coolant leak near pump

Reply #11 –
I believe my leak is at the Transfer Flange.  There is an O ring that is placed on the flange before inserting into the water pump.  Probably 24 years old and in need of replacing.  The attached photo was found on the Cummins Parts website.  Number 22 is a 0.2" x 1.75" x 1.75" O ring, part #  3892095.  I am going to wait to change until better weather.  I appears that the leaks stops when the engine warms up to better than 32 degs F.  The rubber gets pliable or expands as most people have noticed.

Jerry Poettker
1999 U320 40' Special Edition