Radiator hose extremely hard when hot

[Charles F.]

68, L36, had overheating problems when shut off (puked coolant), now has 22 pound radiator cap, runs cool (about 185) and does not puke coolant when shut off.

Question: when running, the upper radiator hose is as hard as plastic pipe. When the engine is shut off, the hose returns to usual flexibility. Is this normal; a function of the radiator cap pressure; or, a sign that something else is wrong ?

Thanks.

Chuck Faillace

[Clem Z.]

Re: Radiator hose extremely hard when hot

68, L36, had overheating problems when shut off (puked coolant), now has 22 pound radiator cap, runs cool (about 185) and does not puke coolant when shut off.

Question: when running, the upper radiator hose is as hard as plastic pipe. When the engine is shut off, the hose returns to usual flexibility. Is this normal; a function of the radiator cap pressure; or, a sign that something else is wrong ?

Thanks.

Chuck Faillace

the pressure in the system is doing this.

[Kenneth T.]

Re: Radiator hose extremely hard when hot

Chuck,

With a 22lb cap, that hose is on Viagra. You are lucky not to spring a leak somewhere. Do you have the system overfilled? If so it will puke until the expansion rate and pressure come to an equilibrium. There is a fill to when cold line which should be well below the cap.

Ken

[Clem Z.]

Re: Radiator hose extremely hard when hot

Chuck,

With a 22lb cap, that hose is on Viagra. You are lucky not to spring a leak somewhere. Do you have the system overfilled? If so it will puke until the expansion rate and pressure come to an equilibrium. There is a fill to when cold line which should be well below the cap.

Ken

just because he has a 22# cap does not mean the system is at 22#

[Charles F.]

Re: Radiator hose extremely hard when hot

The higher pressure cap was used to solve the post-shut down puking problem as we never figured out the root cause. It is a long-standing problem and (with the help of this Board) we suspect it is related to the engine vacuum (which is being looked at again, now).

The system is definitely not overfilled (very aware of this issue) and there are no leaks anywhere that I can see.

This leads to the next issue: the system appears to lose a significant amount of coolant over time (about two quarts within 500 miles) but the oil is not gray and we don't think it is getting in there. The smoke from the tailpipe does not show evidence of water in the combustion process. The engine is newly rebuilt, with less than 3000 miles on it. I hope it is not something internal or the head gasket.

Chuck

[Clem Z.]

Re: Radiator hose extremely hard when hot

find a garage that has a "block tester" and this will tell you if you have combustion gasses in the coolant from either a crack or a leaking head gasket

[Kenneth T.]

Re: Radiator hose extremely hard when hot

just because he has a 22# cap does not mean the system is at 22#

I agree, but not knowing the person and their knowledge and experience,
I look to the simple basics. With no grey oil and no white exhaust, the amount lost may still be coming from a puke while driving, since unlike our taxes, there are only so many places for it to go. Head gasket wrong or a crack. Any bubbles in the coolant with the cap off is another tell. Leak down test may help.

[Charles F.]

Re: Radiator hose extremely hard when hot

The engine was run today without the cap on and there were bubbles in the coolant.

Chuck

[Ray G.]

Re: Radiator hose extremely hard when hot

68, L36, had overheating problems when shut off (puked coolant), now has 22 pound radiator cap, runs cool (about 185) and does not puke coolant when shut off.

Question: when running, the upper radiator hose is as hard as plastic pipe. When the engine is shut off, the hose returns to usual flexibility. Is this normal; a function of the radiator cap pressure; or, a sign that something else is wrong ?

Thanks.

Chuck Faillace

Hello;

Google "combustion gas test kit".

Hope this helps.
Ray

[Clem Z.]

Re: Radiator hose extremely hard when hot

The engine was run today without the cap on and there were bubbles in the coolant.

Chuck

you need to take off the fan belt so the water pump is not turning. the best place to check is in the thermostat housing in the intake manifold with the thermostat removed

[Clem Z.]

Re: Radiator hose extremely hard when hot

Hello;

Google "combustion gas test kit".

Hope this helps.
Ray

some auto parts stores sell these kits if you are into doing it yourself

[Charles F.]

Re: Radiator hose extremely hard when hot

Thanks to all. I see that Napa has such a kit for about $50. Was initially worried about the cost as when I did the Google search, I was getting kit prices in the thousands, but they seemed to be for HVAC. I will check it out.

Chuck

[Charles F.]

Re: Radiator hose extremely hard when hot

I just ordered the kit mail order from Napa (www.napaonline.com) for $49.99 plus tax and shipping. The item is a Leak Detector kit, item # BK 7001006. The web site describes it as:

Manufacturer:Test Tools Inc.
Application:Test For Cracked Blocks
Leaky Gaskets
Cracked or Warped Heads
Product Features:Locates Combustion Leaks w/o Guess Work
Test In Seconds
Removes Guess Work From Job
Additional Contents:Aspirator Bulb w/ Valve
Large Engine Adapter & Leak Test Fluid


I will let you know how I make out with it.

Chuck