O where, o where has my coolant gone?

The place to discuss problems and routine maintenance questions and tips. This is for topics that are specifically diesel-related.
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Rjonesy
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O where, o where has my coolant gone?

Postby Rjonesy » Mon Apr 09, 2018 9:31 am

Wondering if there are any ideas on where I might be losing a small amount of coolant. Since I've gotten the truck I've replaced all by-pass hoses and other coolant supply hoses. Replaced a leaky heater core with a nice used item, buttoned down some slow leaks at the oil cooler and the rat's nest of connections by the oil separator. There is still a slow loss of coolant in the overflow canister. There is no sign of mixing fluids. Wondering if possibly the water pump but don't see anything externally. Maybe 1000 mi. or a bit less to empty the overflow.

Any ideas?

Thanks.

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Skropeling
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Re: O where, o where has my coolant gone?

Postby Skropeling » Mon Apr 09, 2018 2:17 pm

I have the same issue. My coolant turns darker over time and I slowly loose coolant. I see no leaks anywhere and I've tried running it with cardboard under the engine and I see nothing dripping. For me, the leak is slow enough so I can just top off the overflow canister every week or two. Still annoying though, if there's a solution I don't have it, but the slow leak does't seem to be hurting my engine in any way so I don't really see a point in fixing it, although it would be nice to have it fixed. Does your coolant turn darker as well or am I alone in that respect?

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Re: O where, o where has my coolant gone?

Postby jamezg » Mon Apr 09, 2018 3:20 pm

Harbor freight has a coolant (radiator) leak tester.
https://www.harborfreight.com/radiator- ... 63862.html
That and soapy water in a spray bottle will find the small ones.
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Rjonesy
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Re: O where, o where has my coolant gone?

Postby Rjonesy » Mon Apr 09, 2018 3:30 pm

I haven't noticed it getting darker. I refresh it every week or so. Sometimes something small can be a harbinger of something bigger to come but this has been pretty steady.

I guess I'll need to get a bit more desperate before spending 90 bucks on a pressure tester. :?

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swvaed
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Re: O where, o where has my coolant gone?

Postby swvaed » Mon Apr 09, 2018 4:11 pm

Not that knowledgeable on Isuzu diesels, but the gassers and some industrial diesels I know were famous for blown or leaking head gaskets. Watch for lots of white smoke on a cold start (coolant leaking into cylinder) or "bubbling" in the radiator (cylinder pressure leaking into water jacket).
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I'm luving it
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Re: O where, o where has my coolant gone?

Postby I'm luving it » Mon Apr 09, 2018 10:46 pm

When you first start the truck and it’s cold get under truck and look up at the bottom of the water pump where the shaft extends. There should be a small weep hole there. Check there for leaks if it is nasty and corroded clean it off and recheck a couple times. It may leak on start up then the motor heats up and no leak. The leak may also evaporate by the time it gets further down the motor.
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Re: O where, o where has my coolant gone?

Postby dorf » Tue Apr 10, 2018 6:26 am

Purchase or rent a pressure tester that attaches to the raditator fill port. You can pump it up to above normal system pressure and actually see where yourr collant is escaping

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Rjonesy
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Re: O where, o where has my coolant gone?

Postby Rjonesy » Tue Apr 10, 2018 10:08 am

Thanks for the tips.

dorf
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Re: O where, o where has my coolant gone?

Postby dorf » Tue Apr 10, 2018 12:35 pm

You're welcome

Let everyone know the outcome...cheers ......

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Rjonesy
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Re: O where, o where has my coolant gone?

Postby Rjonesy » Sat Apr 14, 2018 7:29 pm

Found it!
Borrowed a pressure tester from Auto Zone. Feel kinda silly as it was right up front. The top radiator hose had a tiny leak at the thermostat housing. In fact it was somewhat intermittent. Must have been so slow it evaporated from engine heat and maybe closed up some when hot. With a cold engine and pumped a couple of pounds high it showed right up.

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Re: O where, o where has my coolant gone?

Postby puttputtinpup » Sun Apr 15, 2018 5:00 am

Rjonesy wrote:Found it!
Borrowed a pressure tester from Auto Zone. With a cold engine and pumped a couple of pounds high it showed right up.

That's a whole lot better than this:
Rjonesy wrote:I guess I'll need to get a bit more desperate before spending 90 bucks on a pressure tester. :?


Way to go! Glad you were able to find it w/o spending a fortune

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Rjonesy
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Re: O where, o where has my coolant gone?

Postby Rjonesy » Sun Apr 15, 2018 8:58 pm

:D :D :D