Latest Issue....coolant Overflow On Engine Switch Off.

[Guest tmarryat]

Having finally solved the indicator issues I've had the car running today, just long enough for it to start raining while sorting the garage! Temperature is reporting normal, between 88 and 92 sitting idling (viscous fan) but engine bay seems hotter than normal. Having had the car idling for around 30mins I switched her off only for the radiator to gush coolant into the overflow bottle and then onto the floor. Previous the overflow tank was about half full after starting empty. After spilling out the radiator pulled the remainder back as it cooled.

 

A provisional google suggests possible head gasket. Any other opinions? The rad cap has just been replaced as the rubber had perished in the original. Cap is the same pressure as previous one, 1.1bar iirc.

 

Edit- this is a 1.6 pinto

Edited April 5, 2014 by tmarryat

[Guest peter2b2002]

might be an air lock or fit a bigger over flow tank, left my 2b on tick over while waiting for its mot for 45 mins as i had to jump start it this morning(flat battery) temp got up to 110 deg before i turned on the heater when down to 100 even with the electric rad fan running but when i drove the mot guy down the road for the brake test it dropped down to 90 no water lost ( my over flow tank takes 2 ltrs)

peter2b

[Al Milton]

Was the expansion (overflow) bottle too full at first, therefore it didn't have enough empty capacity to contain the expanded coolant, therfore it was dumped overboard?

 

The expansion should just have enough coolant when cold to cover the dump/draw pipe inside it. (Can't think how to best to describe!).

My expansion bottle has about an inch of coolant when cold, which rises to about 2.5inches when hot.

I have also marked the bottle so I know what the normal volumes are.

[Longboarder]

Unlikely to be head gasket. That blows air into the water while running in a progressive way. Unlikely to be air lock as that tends to discharge water as it warms up as air expands more than water although that can lead to a localised hotspot in the head. Most likely to be heat soak from a hot spot in the head or just overall below par cooling efficiency leading to localised boiling when the water is stationary after switching off. Usual checks for cooling efficiency.

 

Nigel

Edited April 5, 2014 by Longboarder

[alanrichey]

When that happened to me I eventually traced it to a poorly fitting cap on the expansion bottle. (It's a Superspec so that is the equivalent of the radiator cap)

[Guest tmarryat]

Thanks chaps.

 

The overflow is small, not sure on capacity but it's from a go kart so not massive by any stretch of the imagination. There was nothing in it when I first started (had topped up rad but left empty for expansion)

 

I had anticipated an air lock as system was drained for recent bike carb addition, but I believe I've done everything to eliminate it. Rad cap is highest point in the system as no heater and pipe to carb runs under head level until the manifold.

 

I've just had the rad cap off to check level and tighten it back on. Seems secure against the neck .

 

Could be heat soak from the no coolant circulating. It was just very sudden! Onto eBay to search for larger expansion tank I think!

[kevin the chicken]

Make sure you have the right pressure radiator cap fitted. i think I saw on another post about cooling that you need the 14lb one. As you say it could be heat soak when you turn the engine off causing a localised boil up and ejection of water. When I had air in my Redtop it caused the water to gush out of the top of the radiator with the cap off and through the overflow with the cap fitted. As you have drained the system I presume you have changed the plumbing in some way so make sure you have got everything right. There are plenty of people on here with the same engine who should be able to help. Persevere with it, I know how frustrating it is kneeling in pools of expensive coolant on the garage floor but you will get there, I think I have.

Kevin

[Guest chris brown]

In the first place I would fit a larger expansion bottle at least 1ltr 1.5 would be better mine would pump out about 1ltr if eft running static then switched off yet if driven hard and switched off it dumped much less into the bottle.

[fry61]

A lot of above is to do with that great big radiator sometimes called an engine not being sat in an airflow. The big fans used at r/roads ain't just to blow air in the finned conduction/convection device. Picky I know -- what do you expect from an old fart who counts beans.

 

And picking myself up - the engine doesn't radiate a lot most is conduction/convection.

Edited April 5, 2014 by florin metal works
Factual error

[Grim]

Check your rad cap has 2 seal correctly fitted. If not it may not pressurise the system and cause the problems you describe. As it was the last thing you changed it'd be the first place i'd look

[fry61]

Just my own thoughts Richard --- but the surface area of the engine -- block/head/sump & covers is huge so air flow is needed to take that temperature down.

[Guest Gargoil]

Get rid of the viscous fan and fit an electric one. The engine driven fan doesn't do a lot if it isnt sealed/ducted around the radiator. I had a similar problem and by allowing the fan to run after the engine was switched off, it never happened again. That will cure the symptoms, but you may need to upgrade other items too.

[Guest tmarryat]

Thanks guys. I've ordered a Clio mk2 header/expansion tank which will hopefully get fitted next weekend.

 

Cap is correct two seal one and does seem to be sealing both internal in the neck and external on the rad.

 

Florin your comment makes sense, although it was partially externally water-cooled during this period; didn't quite realise the rain was so heavy until found a puddle on the drivers seat!

 

Gargoil - it's on the never-ending, always increasing to-do list!