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        General >> Give/Need advice to/from others >> Coolant surging and overflowing
        
(Message started by: wolfblood on Feb 7^th, 2010, 8:58pm)

Title: Coolant surging and overflowing
Post by wolfblood on Feb 7^th, 2010, 8:58pm

Hi guys

I have just fitted a new hose following problems with a leak see here for details:
http://www.fordscorpio.co.uk/cgi-bin/yabb/YaBB.pl?board=Advice;action=display;num=1262101495;start=15#18

The latest issue is in filling the coolant.

We filled it up let the engine run to get warm waiting for the fans to kick in but instead about 5 minutes later the expansion tank just overflowed.

Tried it about 5 times incase there was an airlock same thing every time about 5 minutes from starting the engine (engine already warm so didn't have to wait for it to get to temperature) the expansion tank overflowed dumping an absolute shedload of water.

I did notice the top inlet pipe on the expansion tank was blocked so we cleared that out same thing happened again.

System has had a headgasket leak check and no issues found.

We are both at a loss on this one.

Title: Re: Coolant surging and overflowing
Post by PJDavis on Feb 7^th, 2010, 10:28pm

I wonder if after filling the system you should start the car with the expansion tank cap removed, and let the system warm up gradually. There is an air valve in the system, and this should be opened to allow the air to rise, just like when you open a lemonade bottle. What engine are you talking about?

Title: Re: Coolant surging and overflowing
Post by wolfblood on Feb 7^th, 2010, 10:47pm

Hi PJ
Thanks for your reply.
Its the 24V BOB. We actually kept the cap off three times so we could watch and make sure any airlocks were removed. It was weird actually the coolant level held constant then all of a sudden just whooshed up.

Title: Re: Coolant surging and overflowing
Post by Jonnycab on Feb 8^th, 2010, 10:01am

If it's airlocked then try pulling of the the small pipe (middle pipe on cossie) from the expansion & shove a bit of transparent tube (about 3 feet long) in it & attach the other end high up on the bonnet. Start the car & let it warm up, then give it a few revs & any air in the system should be expelled via the tube. When hot, turn engine off & let any more air pockets/bubbles naturally rise up & make their way out of the tube.

Have you checked all pipes for blockages....ie. when engine is hot, are all the pipes hot ?

You say you replaced the water pump, so the only other thing I can think of at the moment is a jammed shut thermostat or a blocked rad :-/

Hope this helps :)

Title: Re: Coolant surging and overflowing
Post by wolfblood on Feb 8^th, 2010, 11:55am

Cheers Johnny
Was wondering about the pump myself. Even though it is new I suppose there is always a chance it is faulty and it is still in its warranty period. It's just a case of finding a way to test it.

Title: Re: Coolant surging and overflowing
Post by Jonnycab on Feb 8^th, 2010, 12:31pm

If the pump is brand new, then I doubt that is problem. They only usually stop working if the impellor comes loose of the pulley spindle or the impellor blades have disintigrated :)

Title: Re: Coolant surging and overflowing
Post by Highlander on Feb 8^th, 2010, 12:59pm

Try cleaning the valve inside the cap or try a new one.

If the valve doesnt close properly it will leak

Title: Re: Coolant surging and overflowing
Post by wolfblood on Feb 8^th, 2010, 2:40pm

Cheers Highlander

Am reticent to try it with the cap on yet as it surges even while the cap is off. Don't want to try it with a cap on until I have figured out why it is surging.

Title: Re: Coolant surging and overflowing
Post by Simmo on Feb 8^th, 2010, 2:47pm

Jonnycab has posted above BUT, at my request, he has posted separately his full advice, together with photographs. This is now a permanent feature of Give Advice' along with other 'regular' issues. ;)

Title: Re: Coolant surging and overflowing
Post by wolfblood on Feb 11^th, 2010, 7:52pm

Hi guys.

Thanks for all the feedback.
Hooked a longer hose up as detailed in Jonnycabs advice and saw the bubbles.
Problem is everytime I added any throttle there were enough bubbles to send the coolant out of the top. As the water level in the expansion tank didn't fall the mechanic has said it has to be the Head Gasket as the extra air that was pushing the coolant had to come from somewhere.
Was surprised as it passed one of those sniffer tests a couple of weeks ago and there are no other signs, but I cannot fault his logic. :'(

Title: Re: Coolant surging and overflowing
Post by Tompion on Feb 11^th, 2010, 10:14pm

Bit of a rash conclusion, try putting a funnel into the hose to allow the air to escape & the water to go back down.

Title: Re: Coolant surging and overflowing
Post by Jonnycab on Feb 12^th, 2010, 1:50am

If it's not the head gasket, then it must be taking in air somewhere......have you checked for leaks all around the cooling system....pipes, radiator etc. Is it possible that the heater matrix has a leak ? :-/

Tompion....do you reckon a funnel at the end of the tube would help even more ? :)....I thought the tube was long enough so that air would easily make it's way passed any rising coolant.....the law of gravity & all that ;)

Title: Re: Coolant surging and overflowing
Post by Simmo on Feb 12^th, 2010, 6:35am

Jon, I reckon Dave's idea is that the air would be able to escape but any 'overflow' would, within reason, be held in the funnel. Do we have a JC method Mk2 !!. ;D. ::)

Title: Re: Coolant surging and overflowing
Post by Jonnycab on Feb 13^th, 2010, 10:13am

Hmmm.... ;D

Title: Re: Coolant surging and overflowing
Post by wolfblood on Feb 25^th, 2010, 9:37pm

OK Guys
Here is todays trial.
Today was the first time I have had to go to the garage where the car is stored. Filled her up with water/coolant got her to temperature and then about 10 mins later had an overflow.
Turned the engine off until it had gone back down. Then refilled with warm water/coolant and fired her back up. Fairly quick to get to temperature and did a test with a piece of kit for a head gasket leak no change in the colour so everything looking fine.
Once again about 10 mins later there was a surge and the expansion tank overflowed.
Given that it was a sudden surge, almost like a gate opening, started to think laterally and removed the thermostat putting a 32mm T pipe in its place.
Filled with warm water/coolant so it wouldn't take as long to get to normal temperature and fired her up. This time she ran for about 25 minutes and did 4 checks for gasket failure all came back with no change of colour. So looked fine as far as a gasket leak is concerned.
My mate who is an experienced mechanic is certain it is a head gasket failure and started to query whether the tester worked so put it by the exhaust and sure enough there was a colour change so looks like the test should detect a leak. (Even changes colour if you breathe into a bottle with some of the liquid in it a few times).
At all times the temperature gauge was at the normal half way point but the fans didn't kick in.
This got me thinking. what if the coolant is actually getting too hot but not registering. How long would you expect before the fans kick in?
Is there a way of checking they are working without OBD.
The fans do both work if aircon is switched on.
???
Dean

Title: Re: Coolant surging and overflowing
Post by wolfblood on Mar 7^th, 2010, 2:15pm

Had a chance to get an hour or so looking at the car again today.
Disconnected the sender for the fans to put various resistors into the circuit and finally got them to come on fast.
Noticed the temp guage in the car had shot up to full.
Identified this as a problem with what I assume is the temp guage sender (which is quite close to the sender for the fans so could easily have been knocked when I disconnected the fan sender) as when I wiggled it the temp went back to half way.
No overflow at all while fans running at full speed and the temp guage shot back down to almost nothing.
As I said above it looks like there might be a problem with the temp guage sender and as the fans only kick in when the sender unit for them (ECT?) is disconnected that looks dodgy too.
Will try and find replacements for these and report results.

Title: Re: Coolant surging and overflowing
Post by wolfblood on Mar 13^th, 2010, 4:17pm

OK
Todays task was to fit the sensor that goes to the dashboard and the one that goes to the fans.
First of all removed the one going to the dashboard and found it had actually snapped in two which would explain the variances each time it was nudged.
If you are quick and cover everything nearby with a cloth there is actually no need to drain the coolant. Was quick enough to remove the old one and plug the new one in that I doubt I lost half a cup of coolant.
With this done moved on to the more difficult task of the fan sender.
This is only more difficult due to two things. The size of the nut part (about 25mm or 26mm at a guess) and its location (you have to fiddle below the top hose).
Before I removed the old one I tested that the new one worked by starting the car (no fans running) connecting the new one to the multiplug wiring and dunking it into a cup of just boiled water (carefully). The fans came on on high then when the sensor was removed from the water they went to half speed. When the sensor was held in the airfow the fans died down as it cooled down.
So off to Halfords to find the right size double depth socket. Guess what they don't stock it so got a 27mm one for £7.00 to try.
Good enough to work.
It is worth noting that I could feel the old sensor was not screwed in the whole way about 8mm or so was the gap between the engine and the brass nut collar part (not sure of the proper name).
Once again if you are quick at changing over and make sure everything else is covered you can get the old one to finger tightness to remove it and quickly put the new one in without losing too much coolant.
With the new one in place tightened it up and checked with my fingers to make sure it was all the way home.
Reconnected multiplug to the old sensor and dunked this in some more freshly boiled water and no fans this time so it looks like the sensors could have been a reason for the car constantly over pressuring as the coolant could have boiled without any fans to cool it and the dash guage not giving me any clues.
Multiplug connected to the newly installed sensor and have run the car for about an hour without any over pressure (in fact I can unscrew the expansion tank cap without hearing any hissing now).
Will run the car for a week or so and hopefully report back that everything is fine.
If this has solved the problems will also do a full breakdown with the photos I took of what has been checked and changed.

Title: Re: Coolant surging and overflowing
Post by Simmo on Mar 13^th, 2010, 4:44pm

Glad to hear that you appear to have cured the problem :). A set of photos would be great. Thanks. :)