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Rad cap drama


supra steveo
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Last night I put my foot down a wee bit to much I think , first time I've done that sine the TT conversion too :( anyway the rad cap spring snapped on the inside of the cap , should this do anything to the expansion tank ? Because it looks like some sort of pressure has blown coolant all over my battery and intake side of the engine so after I pulled the spring part out the top of the rad I topped up both rad and expansion tank with water and limped home :( I picked up a new rad cap today but is there anything else I should be checking ?

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If the spring fails it would vent more then normal, but it shouldn't spray anything out unless the expansion tank was completely full. Obviosly this wasn't the case when you checked as you said you topped up the expansion tank. Maybe the sudden release of pressure unseated the cap temporarily and allowed coolant to vent directly intot he engine bay rather than into the expansion tank?

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That's odd. It should be full when the engine is hot. I think your coolant ran low a while before you spotted the problem. FWIW the spring on my rad cap fell apart some time ago and I never even noticed it. The expansion bottle never filled up or spewed out. Mind you I have a stock NA and you have a modded TT, so you will be loading the cooling system up more.

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Top the rad up till its full and fill the expansion tank to approx half full

or between the min & max lines when the system is cold.

 

With coolant preferably and never tap water.

 

Fit your new cap and take it for a run, is your heater blowing nice hot air ?

 

After its cooled back down check what the level in the expansion tank is as it might

need topping up and keep checking it for a few days.

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Top the rad up till its full and fill the expansion tank to approx half full

or between the min & max lines when the system is cold.

 

With coolant preferably and never tap water.

 

Fit your new cap and take it for a run, is your heater blowing nice hot air ?

 

After its cooled back down check what the level in the expansion tank is as it might

need topping up and keep checking it for a few days.

 

Seeing that there were no abnormal temps, roll with this suggestion and see what it yields. You are not going to do any damage unless you are running extremely high temps or the pump is not getting any fluid to run though it as its running.

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Yeah I've topped up the rad and the expansion tank with water took it for a spin with the new rad cap fitted and when I got back it looks like the expansion tank has been getting top up with coolant coz now it's red and over the full mark , think I am still goin to do a full coolant change coz now the coolant is watered down :(

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Yeah I've topped up the rad and the expansion tank with water took it for a spin with the new rad cap fitted and when I got back it looks like the expansion tank has been getting top up with coolant coz now it's red and over the full mark , think I am still goin to do a full coolant change coz now the coolant is watered down :(

 

If you topped up the rad and the expansion tank then it would be normal for the tank to be over full while the engine was hot. When it cools down the level in the tank should go back to where you filled it.

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