Any risk in swapping radiator caps?

[billschroeder5842]

Is there any downside to replacing my current 15lb cap and putting a 13lb radiator cap on the tank?

I'm thinking of doing this at the suggestion (dare?) of a couple of car buddies who think that it will help me eliminate the coolant seep around my heater hose (I did get the replacement part from Jerry's, and am waiting for it to "get worse") attached to the thermostat housing.

The theory is that the lower pressure cap will allow the hot coolant to escape into the radiator overfill tank, bypassing and not not forced out of the heater fittings.

I'm really getting only a modicum of seepage now and the thought is that going from a 15 to a 13 will allow the coolant to escape through a lower pressured area thus eliminating the seepage.

Sounds easy huh?

Before I swapped caps, I thought I ask and get a few opinions as to if thee is any foreseeable risk.

Thanks!

[RussMcB]

Is there any downside to replacing my current 15lb cap and putting a 13lb radiator cap on the tank?Yes, but it's pretty small. Your cooling system will boil over at a slightly lower temperature. IOW, you will have slightly less protection from boiling over - Maybe 2-4 degrees less.

[Hog]

The higher the cooling system pressure, the reduced propensity for pump cavitation. I'd guess that 2 lbs wouldn't make a huge difference, but it's pure speculation on my part.

[Mystic ZR-1]

FWIW: My stock/original cap is 17#...

[Roadster]

I had a 15 lb cap on mine and went up to a stock spec 17lb.cap.
From what was explained to me is that the higher you go up in a pressure cap, the higher the boiling point of the coolant will be. And the lower in cap pressure that you go the opposite is true.

JMO, i dont think it would be good to drop to a 13lb cap. Then you are lowering the boiling point as mentioned, so if your engine starts to get hotter for any particular reason during operation, then you would have a greater chance of overheating, because you have decreased the "cushion" that the engine was designed for...

Going from a design spec 17lb cap to a 15lb cap is one thing, dropping to a 13lb cap is another.
Again JMO....
The group engineers would be able to give you realistic advice...

You should address the issue completely and not have to be concerned with it in the future.


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[Roadster]

Yes, but it's pretty small. Your cooling system will boil over at a slightly lower temperature. IOW, you will have slightly less protection from boiling over - Maybe 2-4 degrees less.

I was under the impression it would be more than a 2-4 degree difference, a much more larger spread, or maybe not....
If you are already running a 15lb.cap, then you already dropped your boiling point 2-4 degrees from the stock 17lb. cap, if that is all the difference is, so if you went down to a 13lb. cap now you are 4-8 degrees lower with the boiling point, again if that's all the spread is.

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[Roadster]

Some interesting info....

http://www.tuneruniversity.com/blog/2011/06/beating-the-heat-advantage-of-a-high-pressure-radiator-cap/

http://www.carsdirect.com/car-repair/understanding-radiator-cap-pressure-ratings

[Ozruss90]

I'm thinking of swapping over to Evans waterless coolant. Has anyone had any experience with this product? Sounds good in theory.

[32valvesftw]

If you have leaks at 15lbs you will probably have leaks at 13lbs

[RussMcB]

Have you tried to find a local place that has loaner tools or can test your cooling system pressure for you? (As mentioned before) That will tell you exactly what you need to know in order to decide what you should do to fix the problem.

http://www.autozone.com/landing/page.jsp?name=loan-a-tool

[A26B]

Have you tried to find a local place that has loaner tools or can test your cooling system pressure for you? (As mentioned before) That will tell you exactly what you need to know in order to decide what you should do to fix the problem.

http://www.autozone.com/landing/page.jsp?name=loan-a-tool

I concur with this recommendation.

Reducing the system pressure is a patch on a likely small problem that can result in premature boil-over in an engine that is somewhat prone to overheating in certain conditions. With summer coming on, it's the best time to make sure the cooling system is in top condition.