GMCforum
For enthusiast of the Classic GMC Motorhome built from 1973 to 1978. A web-based mirror of the GMCnet mailing list.

Home » Public Forums » GMCnet » Coolant puddle on intake manifold
Coolant puddle on intake manifold [message #349838] Sun, 03 November 2019 16:19 Go to next message
MikeB is currently offline  MikeB   United States
Messages: 133
Registered: December 2018
Location: South Bama
Karma: 1
Senior Member
Yesterday I decided to take the MH into town to fill the tanks and give it my Monthly 40 minutes of driving. Before I left I looked at the motor and found a few puddles sitting down on the right side of the intake manifold. It was probably a few table spoons in each lower indent. I soaked it up with paper towel. I dint see any cracks or evidence of where it may have come from. There is one fairly new heater hose that runs on that side and connects to the rear. I checked that hose for evidence, looseness of clamps and everything on it was clean and tight. After my in town run I checked and there was no additional anti-freeze puddled. I also checked all hose connections, water pump, etc for signs of seepage and I didn't see anything. The PO installed a new aluminum heavy duty WP from applied this last summer.

I couldn't see evidence of the source of the leak but I'm wondering if this is a symptom that y'all have seen before? Could coolant be seeping out at manifold bolts?

The manifold is aluminum.

Thanks
Mike


M Beam 75’ Avion TBI EBL , 3.70 LSD and other stuff Zuki Sidekick, Dozier Al
Re: [GMCnet] Coolant puddle on intake manifold [message #349840 is a reply to message #349838] Sun, 03 November 2019 16:35 Go to previous messageGo to next message
James Hupy is currently offline  James Hupy   United States
Messages: 6806
Registered: May 2010
Karma: -62
Senior Member
Depends upon which intake manifold you have, and whether or not your deck
surfaces and heads have been milled. If, that is the case, and the angles
between the intake and heads are not correct, and you have an early model
Rockwell manifold, your intake-to-head gaskets might easily be misaligned.
That can and does lead to antifreeze coolant leaks.
Jim Hupy
Salem, Oregon

On Sun, Nov 3, 2019, 2:20 PM mtb8114--- via Gmclist
wrote:

> Yesterday I decided to take the MH into town to fill the tanks and give it
> my Monthly 40 minutes of driving. Before I left I looked at the motor and
> found a few puddles sitting down on the right side of the intake manifold.
> It was probably a few table spoons in each lower indent. I soaked it up
> with paper towel. I dint see any cracks or evidence of where it may have
> come from. There is one fairly new heater hose that runs on that side and
> connects to the rear. I checked that hose for evidence, looseness of
> clamps and everything on it was clean and tight. After my in town run I
> checked
> and there was no additional anti-freeze puddled. I also checked all hose
> connections, water pump, etc for signs of seepage and I didn't see anything.
> The PO installed a new aluminum heavy duty WP from applied this last
> summer.
>
> I couldn't see evidence of the source of the leak but I'm wondering if
> this is a symptom that y'all have seen before? Could coolant be seeping out
> at
> manifold bolts?
>
> The manifold is aluminum.
>
> Thanks
> Mike
> --
> M Beam
> 75’ Avion
> TBI EBL , 3.70 LSD and other stuff
> Zuki Sidekick,
> Dozier Al
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Re: Coolant puddle on intake manifold [message #349843 is a reply to message #349838] Sun, 03 November 2019 17:30 Go to previous messageGo to next message
Dennis S is currently offline  Dennis S   United States
Messages: 3046
Registered: November 2005
Karma: 2
Senior Member
Just a caution
Before you drive any more check the oil for signs of coolant. If it's leaking outside it may also be leaking internally.

Dennis


MikeB wrote on Sun, 03 November 2019 16:19
Yesterday I decided to take the MH into town to fill the tanks and give it my Monthly 40 minutes of driving. Before I left I looked at the motor and found a few puddles sitting down on the right side of the intake manifold. It was probably a few table spoons in each lower indent. I soaked it up with paper towel. I dint see any cracks or evidence of where it may have come from. There is one fairly new heater hose that runs on that side and connects to the rear. I checked that hose for evidence, looseness of clamps and everything on it was clean and tight. After my in town run I checked and there was no additional anti-freeze puddled. I also checked all hose connections, water pump, etc for signs of seepage and I didn't see anything. The PO installed a new aluminum heavy duty WP from applied this last summer.

I couldn't see evidence of the source of the leak but I'm wondering if this is a symptom that y'all have seen before? Could coolant be seeping out at manifold bolts?

The manifold is aluminum.

Thanks
Mike


Dennis S
73 Painted Desert 230
Memphis TN Metro
Re: [GMCnet] Coolant puddle on intake manifold [message #349850 is a reply to message #349843] Sun, 03 November 2019 22:29 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
Senior Member
Pressurise the cooling system with a coolant pump up to 20-25 psi and watch
for leaks.
Should be able to rent one at a parts store.


On Sun, Nov 3, 2019 at 3:31 PM Dennis Sexton via Gmclist <
gmclist@list.gmcnet.org> wrote:

> Just a caution
> Before you drive any more check the oil for signs of coolant. If it's
> leaking outside it may also be leaking internally.
>
> Dennis
>
>
> MikeB wrote on Sun, 03 November 2019 16:19
>> Yesterday I decided to take the MH into town to fill the tanks and give
> it my Monthly 40 minutes of driving. Before I left I looked at the motor
>> and found a few puddles sitting down on the right side of the intake
> manifold. It was probably a few table spoons in each lower indent. I soaked
> it
>> up with paper towel. I dint see any cracks or evidence of where it may
> have come from. There is one fairly new heater hose that runs on that side
>> and connects to the rear. I checked that hose for evidence, looseness of
> clamps and everything on it was clean and tight. After my in town run I
>> checked and there was no additional anti-freeze puddled. I also checked
> all hose connections, water pump, etc for signs of seepage and I didn't see
>> anything. The PO installed a new aluminum heavy duty WP from applied
> this last summer.
>>
>> I couldn't see evidence of the source of the leak but I'm wondering if
> this is a symptom that y'all have seen before? Could coolant be seeping out
>> at manifold bolts?
>>
>> The manifold is aluminum.
>>
>> Thanks
>> Mike
>
>
> --
> Dennis S
> 73 Painted Desert 230
> Memphis TN Metro
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>


--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmcrvparts.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org



Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
Re: Coolant puddle on intake manifold [message #349854 is a reply to message #349838] Mon, 04 November 2019 01:18 Go to previous messageGo to next message
Ken Burton is currently offline  Ken Burton   United States
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
Senior Member
Do not get carried away with all of the difficult possibilities. Instead go look for the easy and most likely things first first.

For example look at hoses and hose connections. They are on top of the manifold and it is logical that they would puddle antifreeze there.

Next would be the thermostat housing and gasket. The one that really threw me off for a while was thermostat housing bolts. They go through the housing and the manifold and into the coolant carrying area. I once had some leaking up through the threads of those bolts. The fix was simple. Remove them one at a time and put some sealant on the bolt threads. I used aviation permatex.

After looking at all of that, then you can look at more difficult things to fix.

A cooling system pressure tester can also help by pressurizing the whole system COLD and watching for leaks WITHOUT the engine running. Do not go over 10 PSI.


Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Re: Coolant puddle on intake manifold [message #349859 is a reply to message #349838] Mon, 04 November 2019 07:19 Go to previous messageGo to next message
jhbridges is currently offline  jhbridges   United States
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
Senior Member
Also, do not think the tester set loaned by Advance will work. It won't. You will have to sacrifice a radiator cap and make it into an inlet for pressure. Last resort that is.

--johnny


Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell
Re: Coolant puddle on intake manifold [message #349874 is a reply to message #349838] Mon, 04 November 2019 15:57 Go to previous message
MikeB is currently offline  MikeB   United States
Messages: 133
Registered: December 2018
Location: South Bama
Karma: 1
Senior Member
Thanks for the tips. I'll follow up when I find something out.

M Beam 75’ Avion TBI EBL , 3.70 LSD and other stuff Zuki Sidekick, Dozier Al
Previous Topic: [GMCnet] Advice and Lessons Learned?
Next Topic: Help
Goto Forum:
  


Current Time: Thu Nov 07 20:37:26 CST 2024

Total time taken to generate the page: 0.00898 seconds