Coolant Leak Near Heater Core on Chevy Workhorse 8.1L

[JoelP]

I noticed that my coolant level dropped significantly after each trip. Then I saw that coolant was dripping from the housing that surrounded the heater core. Has anyone had experience with a leak of this type for the Chevy Workhorse 8.1L chassis? I am guessing that I either have a leaky hose inside that housing, a leaking heater core inside that housing or maybe a poor connection from a heater hose to the core.

Thanks!

Joel

 

[8Muddypaws]

Any of those is a reasonable guess. Chances are getting to it will be the biggest problem. They’re usually buried deep in the dash.

 

[Lou Schneider]

Hoses connect outside the enclosure. You have a bad heater core.

 

[John From Detroit]

I noticed that my coolant level dropped significantly after each trip. Then I saw that coolant was dripping from the housing that surrounded the heater core. Has anyone had experience with a leak of this type for the Chevy Workhorse 8.1L chassis? I am guessing that I either have a leaky hose inside that housing, a leaking heater core inside that housing or maybe a poor connection from a heater hose to the core.

Thanks!

Joel

As Lou said, No hoses inside the housing it's the core.

In the old days that was an easy fix.. but today as Lou said it is often buried in the dash.

Also the core is a body builder item, not an engine make item though GM may have provided it mounting is up to the body builder.

If it is obvious how to get it out do so. If not.. What Lou said.

 

[JoelP]

I had it pressure tested and surprisingly it passed the pressure test. The surprising thing is that one of the hoses leaked that was connected to the core but only leaked when some pressure remained and it had cooled down. At the suggestion of a wise old chassis mechanic I clipped 3/8” off the end of the hose and reattached it. The leak now seems to be gone. What a relief that I don’t have to remove the difficult to access the heater core. I consider this issue now closed but wanted to post this to possibly help someone else.

 

[JoelP]

Hoses connect outside the enclosure. You have a bad heater core.

See below. It was leaking from a hose, but not when hot so I initially failed to see the hose leak.

 

[House Husband]

I once had a loose heater hose clamp that allowed coolant to flow across the heater core tube and inside the housing. Check your clamps first.

Richard