xell Posted April 12, 2007 Share Posted April 12, 2007 Hi guys, I went for "spirited" drive last night and all was fine. Temp gauge in the middle, car running fine. I let it cool down and turned the engine off. I came back to the car 5 minutes later and I could hear water boiling! I looked under the bonnet and the water in the radiator sounded like it was boiling!! I had a look under the car etc but nothing was leaking. Anyone have any ideas what this could be? Its a bit worrying. Quote Link to comment Share on other sites More sharing options...
Daston Posted April 12, 2007 Share Posted April 12, 2007 rad cap gone? Quote Link to comment Share on other sites More sharing options...
xell Posted April 12, 2007 Author Share Posted April 12, 2007 Just had a check and I think i'm dangerously low on coolant! What coolant should I use? Quote Link to comment Share on other sites More sharing options...
Daston Posted April 12, 2007 Share Posted April 12, 2007 I would only use Toyota Red longlife coolant (think thats the stuff) Quote Link to comment Share on other sites More sharing options...
ManwithSupra Posted April 12, 2007 Share Posted April 12, 2007 Sounds like you have air in the system Quote Link to comment Share on other sites More sharing options...
absz Posted April 12, 2007 Share Posted April 12, 2007 rad cap gone? theres your answer:) Quote Link to comment Share on other sites More sharing options...
Ric Posted April 12, 2007 Share Posted April 12, 2007 sure it wasnt the charcoal canister making its usual noises, strange for coolant to boil AFTER you have turned the engine off Quote Link to comment Share on other sites More sharing options...
Kranz Posted April 12, 2007 Share Posted April 12, 2007 strange for coolant to boil AFTER you have turned the engine off Its normal for the coolant in the head to boil after shutdown following a 'spirited' drive as the cylinder head temps are still locally high at the combustion chamber. This heat passes through to the coolant around the combustion chamber and heats it a huge amount (called heat soak). As there is no flow, and the top of the head is the highest point, the coolant boils in the head causing steam to be released and bubbles to pass through to the rad. Race cars fit electric water pumps to avoid this after shut down. Idling the engine for a couple of minutes to allow things to settle down will help. Quote Link to comment Share on other sites More sharing options...
Guest nightreaper Posted April 13, 2007 Share Posted April 13, 2007 mine does the same its pissing me off couse i dnt knw if my car if gonna over heat Quote Link to comment Share on other sites More sharing options...
Mike M Posted April 13, 2007 Share Posted April 13, 2007 Its normal for the coolant in the head to boil after shutdown following a 'spirited' drive as the cylinder head temps are still locally high at the combustion chamber. This heat passes through to the coolant around the combustion chamber and heats it a huge amount (called heat soak). As there is no flow, and the top of the head is the highest point, the coolant boils in the head causing steam to be released and bubbles to pass through to the rad. Race cars fit electric water pumps to avoid this after shut down. Idling the engine for a couple of minutes to allow things to settle down will help. So you could cause damage by turning off too soon due to heatsoak overheating the head. Nasty. Quote Link to comment Share on other sites More sharing options...
Kranz Posted April 13, 2007 Share Posted April 13, 2007 So you could cause damage by turning off too soon due to heatsoak overheating the head. Nasty. Not really, temps won't go high enough to cause any damage. Certainly won't be high enough to warp the head, but will reach 125C. The fact that the heat is dissipating means it wouldn't be a problem. A similar thing would happen if the water pump failed with the engine running.. with dire consequences as the area around the combustion chamber would keep heating up until Quote Link to comment Share on other sites More sharing options...
absz Posted April 13, 2007 Share Posted April 13, 2007 Its normal for the coolant in the head to boil after shutdown following a 'spirited' drive as the cylinder head temps are still locally high at the combustion chamber. This heat passes through to the coolant around the combustion chamber and heats it a huge amount (called heat soak). i was always under the impression that the coolant cannot boil over as long as its under pressure hence the reason for a pressure rad cap. even on shut down. Quote Link to comment Share on other sites More sharing options...
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