Cooling system preasure

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tigertim
Posts: 81
Joined: Mon May 25, 2015 11:06 pm
Location: Kent

Cooling system preasure

Post by tigertim » Mon Jun 08, 2015 10:57 pm

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

bobvic
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Joined: Mon Mar 02, 2015 8:55 pm

cooling problem

Post by bobvic » Tue Jun 09, 2015 8:25 pm

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.

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redbaron
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Location: Essex

Cooling system preasure

Post by redbaron » Tue Jun 09, 2015 8:39 pm

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.

tigertim
Posts: 81
Joined: Mon May 25, 2015 11:06 pm
Location: Kent

Post by tigertim » Tue Jun 09, 2015 9:50 pm

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?

tigertim
Posts: 81
Joined: Mon May 25, 2015 11:06 pm
Location: Kent

Post by tigertim » Wed Jun 10, 2015 2:29 pm

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

Tim
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Post by Tim » Fri Jun 12, 2015 10:47 am

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

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pushrod
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Post by pushrod » Tue Jul 14, 2015 12:15 am

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
65 Mk1 Tiger 260
66 Mk1 Tiger 260 (African Violet)
63 Ford Falcon Sprint
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redbaron
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Cooling system preasure

Post by redbaron » Tue Jul 14, 2015 8:59 am

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.

Tim
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Joined: Fri May 06, 2011 4:00 pm
Location: Wiltshire

Post by Tim » Mon Jul 20, 2015 6:55 pm

Thanks David.

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