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Cooling system preasure

Posted: Mon Jun 08, 2015 10:57 pm
by tigertim
Guys. Got my tiger back in Feb this year, since then renewed the whole cooling system, including a new header tank I had spun to look like the original. Its been running fine with no overheating, have done some 700 miles. This weekend I notice I seem to have excess pressure in the top hose, it comes up solid. all temps still ok, if the engine is warmed up on the drive all seems ok, as soon as I go for a spin just a few miles it comes solid again. Is this normal or I've just not noticed? taken out thermostat and changed rad caps. still no joy.
Tim

cooling problem

Posted: Tue Jun 09, 2015 8:25 pm
by bobvic
I note you have a new Header Tank. Check that the Air bleed pipe and the overspill pipe on the neck are clear ie not blocked by weld from the manufacturing process.

Cooling system preasure

Posted: Tue Jun 09, 2015 8:39 pm
by redbaron
Hello Tim,
the top radiator hose will become hard during and after running,that is due to the pressure in the cooling system,of the hot coolant and gases.
It is also dependent on the Rad Cap vent relief valve setting,what is your cap rated at?
You should always run a thermostat in the system,purely to control the water flow and allow the engine to attain better fuel/running conditions.

Posted: Tue Jun 09, 2015 9:50 pm
by tigertim
Ports all ok, went there first, tried different caps,13 &15 psi also tried type with pressure relief tap.Not happy with that, felt it was sticking some times. stat came out just to eliminate that source so will go back in. I am sure the overflow vent is working as that's how I first noticed a problem with damp under the car after parking.
Going to do a sniff test tomorrow just in case I have a head gasket on the way out.
top hose does look like its about to burst! any more thoughts?

Posted: Wed Jun 10, 2015 2:29 pm
by tigertim
Ok guys, this is what I found. changed back to my old header tank, put 13 psi cap on and bingo we are cooking on gas. Looks like the neck in the new tank is jamming the cap relief. bit more work to do. Tank looks really good will try get some pics up loaded.
Tim

Posted: Fri Jun 12, 2015 10:47 am
by Tim
Just out of interest, what is the correct radiator cap for a Tiger? I assumed that the 13lbs one fittied to my car is correct, but assumption is a dangerous thing...

Also, what is the correct level for coolant in the expansion tank with the engine cold? Another assumption of mine is that it should be half full, but it'd be nice to get confirmation of that.

Thanks

Posted: Tue Jul 14, 2015 12:15 am
by pushrod
13lb standard for a Tiger I believe.

My radiator cap has number 7 stamped on it, so I would assume that's 7lb?
It works fine, did so with the original radiator and now with the new alloy Concept Racing rad.

I run 50/50 distilled water and blue antifreeze.

So potentially I could improve the performance of my cooling system even further by running a higher pressure radiator cap and drop the ratio of antifreeze for summer use and/or replace with water wetter.

Lou

Cooling system preasure

Posted: Tue Jul 14, 2015 8:59 am
by redbaron
Tim,
have the header tank just over the half full when cold to allow for expansion when hot,if you overfill it will expand and lift the cap and let coolant out,finding it's own level.

Posted: Mon Jul 20, 2015 6:55 pm
by Tim
Thanks David.