Leaking coolant & limp mode problem, could they be linked?

[Hammett]

Hi,

 

Been tearing my hair out with this one for a while.  Have been having an issue were car will go into limp mode if at around 3000rpm in third (very common problem I know). Thinking firstly maybe sticky vanes. Have tried putting diesel additives in a couple of times and booting it, seems to fix for a short time.

 

Since about christmas I've been slowly losing coolant very slowly, topped it up thought no more about it. A couple of months ago I was particularly heavy footed on the way to work (25 mile journey) and just before pulling into the car park the coolant warning light came on. After about an hour I noticed that there was a puddle of coolant underneath the driver foot well. I've since noticed that leaking will occur if I cruise anywhere over 70mph on the motorway on the way to work. Have also noticed very small dark specks floating in the coolant reservoir.

 

I've been told that it could be a leak from the water pump, head gasket on the way out or simply just need a new coolant reservoir (this is where I think it's leaking from but can't be sure, not even with UV light at night).

 

As the coolant leak seems to occur at around 3000rpm in 5th I was wondering if these issues could be linked? Possibly EGR valve causing pressurisation of the coolant system and the tiny dark specks. My knowledge is very limited and I'm just guessing.

 

Was going to take it into the dealers but lost quite alot of trust with them now, so going to take to a local reputable garage and see what they say.

 

Anyone had the same issues or any ideas?

[pauldazzle]

The Mr Muscle fix is worth trying for the sticky vane issue.

Leaking EGR cooler is a possibilty, a new headertank is cheap & easy to replace so worth a shot. While you're at it checking for flow from the headertank return pipe might be wise to see if the water pump impellor is still working. Sniff test to check for HG failure would be wise too.

[KenONeill]

Er, 3_000rpm in top would be about 90mph in mine (standard TDi110 Elegance).

[Hammett]

Checked return pipe yesterday and seemed to be flowing well. KenONeill, I think you're right there, my mistake. (also same standard 110 elegance). Not really experienced enough to try the mr muscle fix though. I'll see what the garage says. Thanks for the feedback(s).

[Guest]

I had a very similar problem whilst towing a trailer on holiday, it was fine all the way down the motorway but as I slowed for traffic the low coolant light came on, so I stopped removed the cap topped up and continued then it did the same again. Was fine while on holiday the the same happened in the return journey. I was wondering if it was the coolant bottle? I've had the water pump done when the belt was done, and the coolant has been replaced. I noticed that there was not an excessive amount of pressure when removing the cap, so don't think its head gasket. Might try a new coolant bottle to see if that cures it.

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[Hammett]

My coolant bottle seems to hold the pressure for quite a long time, but I think that's normal.  Something I did fail to mention is that ever since the limp mode started my temp guage seems to dip ever so slightly (maybe 2-3 degrees sometimes) maybe down to the fact I generally have air con all the time and fans are generally on with it, but defintely always used to stay at 90 all the time. CTS maybe?

Edited 19 August, 2015 by Hammett

[Hammett]

Going to try new coolant header tank first. If it still leaks then I suspect head gasket, in that case I'll probably be scrapping it, shame as it's been a great car for nearly 10 minutes and bodywise is still in very good condition.

[STSKODA]

have a good look round for telltale white marks - common areas are the thermostat, coolant temperature sensor too

[Hammett]

Can't really see anything, that part of the car is so packed with pipes etc. Where are they located?

 

Garage couldn't find leak either, they suspect the header tank as there is a bit of crystalisation near overflow. Will get new tank, but suspect head gasket is causing increase in pressure. If it still leaks after that think I may need to look at another car!

[Hammett]

More baffled now. Have had the header tank replaced but it's still leaking, it would appear to be coming from under the coolant tank somewhere, one of the metal pipes looked wet after taking it for a nippy test drive. It seems to be collecting on a plastic shelf above the wheel arch and moving all the way along that shelf to about 6 inches before front of the car. But the water travels down parts of the chassis along to the inside of the wheel then drips there and splashes the surrounding wheel arch. Have been told it could be early signs of head gasket going, but oil and water look ok. Not sure if I should cut my losses at the moment. I doesn't leak if I cruise along to work at 60 for 25 miles, only if I go 65mph+. Any help or ideas would be greatly appreciated.

[StevesTruck]

At risk of asking a stupid question. Did you replace the cap as well or just the expansion tank?

[Hammett]

Both.

[Toxicvrs]

Stop throwing money at it and get it pressure tested, could even use UV dye, best way to do it otherwise you could replace loads potentially that doesn't need to be

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[Hammett]

Exactly my thoughts. Gotta bear in mind though it has done 234,000 miles.