Date: Fri, 23 Sep 2022 07:33:37 -0700
Reply-To: mark@MARKMCCULLEY.COM
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mark McCulley <mark@MARKMCCULLEY.COM>
Subject: Re: cooling system hose clamps
In-Reply-To: <BL0PR05MB4916A592FB3F9AC301969D72A0519@BL0PR05MB4916.namprd05.prod.outlook.com>
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Thank you for weighing in on this Dennis. Today I'm going to get a pressure test kit from Autozone. I'm also going to get a lower pressure cap and road test with it before preemptively tightening any clamps. Make one change at a time so I know what resulted in a fix if there is one.
-Mark
> On Sep 23, 2022, at 4:53 AM, Dennis Haynes <d23haynes57@HOTMAIL.COM> wrote:
>
> Good morning and happy Friday. Hopefully this response goes through.
>
> Coolant system leaks can be illusive. Often I have had vehicles with unexplained coolant issues and sometimes leaks are not apparent even with pressure testing. There are a lot of dynamics in the cooling system and while we tend to pay attention to the "bulk" coolant temperature, things are drastically different with the engine under load as compared to letting the coolant get hot enough to turn on the radiator fan.
>
> Depending on the choice of coolant, most leaks that drip and dry will also leave a dried coolant trail. At hose connections you will often see the salt like corrosion at the sone ends.
>
> For the coolant pressure tank, a major advantage of the aluminum tanks is the use of a standard pressure cap. This style cap is easily inspected and is much more reliable then the plastic molded assembles. Also it is easy to get test set up for both the cap and system. Make the investment. On occasion I have also added a test port somewhere in the system. A Schrader valve can be used to charge the system with air and test including the cap at one time. Also, these tanks usually come with 16 psi caps. Since our systems would only go to 240F during a failure we don’t need near that. 12-14 is more than needed. The heater cores and radiator will thank you.
>
> Places that can be a source of intermittent leaks include the heater cores, especially the front and of course the heads. The heads can lose their tension and cause internal leaks under load. Have the oil tested to ensure coolant is not getting in. Coolant to oil leaks can occur at the base of the cylinders, the head nuts under the rockers, and of course at the top of the cylinders. Usually the top of cylinder leaks often cause other coolant system issues as the combustion gasses will push out and vapor lock the water pump or actually blow some coolant out the relief. Often this only happens under load so it is illusive. The heads can also have cracks in the combustion chambers and for the AMC heads in the exhaust ports. That is a tough one to diagnose. Pull the Cat and see if there is coolant damage.
>
> Since your coolant loss is related to engine operation under load you need to look at what is different during driving as compared to idle operation. If the coolant level goes high in the expansion tank and the pressure tank goes low you need to consider system is not right in the engine.
>
> Hope this helps.
> Dennis
>
>
>
> -----Original Message-----
> From: Vanagon Mailing List <vanagon@gerry.vanagon.com> On Behalf Of Mark McCulley
> Sent: Friday, September 23, 2022 12:38 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: cooling system hose clamps
>
> Yes, the radiator fan was on.
>
> Sent from my iPhone
>
>> On Sep 22, 2022, at 9:24 PM, Alistair Bell <albell@shaw.ca> wrote:
>>
>> Mark.
>>
>> Have you idled until the rad fan comes on?
>>
>> Alistair
>>
>>> On Sep 22, 2022, at 9:10 PM, Mark McCulley <mark@markmcculley.com> wrote:
>>>
>>> Here's another data point:
>>>
>>> I can't reproduce the problem without actually driving the van. If I let it idle in the driveway until coolant and oil temperature comes up to operating level and then run for another 10 minutes there is no coolant smell. If I drive it for 10 or 15 minutes I get the smell.
>>>
>>> -Mark
>>>
>>>>> On Sep 22, 2022, at 7:58 AM, Mark McCulley <mark@markmcculley.com> wrote:
>>>>
>>>> About a year ago I had my cooling system revamped with a new radiator, water pump, stainless steel pipes to the radiator, and many new hoses. Since then I can smell coolant outside the van after driving it. I took it back to the mechanic, said they pressurized the system and found no leaks. There is no evidence to be found of any coolant dripping on the pavement beneath the van, only the smell. On a recent 200 mile trip the van depleted most of the coolant in the overflow tank. The rear heater core is bone dry, that isn't the problem.
>>>>
>>>> The coolant smell is strong on the right rear side so I've been looking at the hoses and connections in that area. I suspect the leak may be at the hose connection on the front of the right head. This connection is above the exhaust outlet so any coolant that leaked would be vaporized and never reach the ground. This connection is a new silicone hose with a new screw-type hose clamp.
>>>>
>>>> My question here is whether an ear clamp (Oetiker style) would be better than a screw-type clamp for this application.
>>>>
>>>> Also part of the revamp was a new aluminum coolant reservoir with a 16lb pressure cap. I've also wondered if the cap might be defective, causing the system to run at a higher than designed pressure.
>>>>
>>>> I spent a lot of $$ so that the all important cooling system would be robust and I wouldn't have to worry about it, very dismayed to have to keep troubleshooting this. I appreciate any observations or comments.
>>>>
>>>> Regards,
>>>> Mark
>>>> '87 syncro
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