Coolant overflow, constant dripping - SOLVED!

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Devon_MR2
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Coolant overflow, constant dripping - SOLVED!

Post by Devon_MR2 » 07/03/17 9:44

Hi, I've noticed when running there is a constant dripping from the coolant overflow pipe. I've replaced the metal coolant top up cap to see if that fixed the problem due to a poor seal but it's had no effect.

Any idea's where to look next ?

Thanks
Last edited by Devon_MR2 on 11/03/17 17:48, edited 1 time in total.

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peteV6R5
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Re: Coolant overflow, constant dripping

Post by peteV6R5 » 07/03/17 12:55

the way the sytem is designed to work is the overflow is actually an expansion tank.
When the coolant get to temp it expands builds pressure and when over 0.9 bar expands into the bottle.
Bet you knew that already.
Now what should happen next is when it cools it caused a slight vacuum in the system which should draw the coolant back in from the expansion tank. As the system gets old (pressure cap gets old and dirty). one of 2 things can happen.
The pressure cap does not allow coolant back in / or the system has a very small leak which allows air in when the system cools.
If you have been checking and topping up your system then my money is on your expansion bottle is full and when up to temp it overflows through the pipe. (get / got same on the V6 as its a long path from pressure cap to expansion bottle)

So 1 check the bottle is only half full.
Check the pressure cap toggle is free
check the pressure cap is clean and free of crud.
same goes for the seat of the filler neck.
Hope that helps
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Devon_MR2
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Joined: 23/11/16 9:37

Re: Coolant overflow, constant dripping

Post by Devon_MR2 » 07/03/17 14:00

Thanks for all the info, I'll take a look through the system again in more detail. The expansion tank is only at half way mark and I've replaced the pressure cap in case that was the problem. The car is my 14 year old sons as a project so I'll pass all the details to him for investigation.

Really appreciate you taking the time to reply.

Devon_MR2
Posts: 21
Joined: 23/11/16 9:37

Re: Coolant overflow, constant dripping - SOLVED!

Post by Devon_MR2 » 11/03/17 17:53

Well Alex (our 14year old) who'es project this is and I did many jobs today including new accelerator cable and a hunt for the cause of the coolant dripping. We are not sure if we should class ourselves as masters of our trade or numpties... after checking everything we and still not solved it we stood back looked at the expansion tank cap, looked each other, took the cap off and found the it was connected the wrong way round! Swop the pipes round and the dripping stops! We will add that the car arrived to us in this state :-)

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pbmr2
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Re: Coolant overflow, constant dripping - SOLVED!

Post by pbmr2 » 11/03/17 18:07

It's all a vital part of the learning process, wish I'd be able to work on cars at his age.
*ECU Fault code reading - How To - Updated link
**BGB/workshop manual download - HERE
*** "Stop buying parts to solve the problem, find out what is wrong first!"

Devon_MR2
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Re: Coolant overflow, constant dripping - SOLVED!

Post by Devon_MR2 » 11/03/17 18:10

pbmr2 wrote:It's all a vital part of the learning process, wish I'd be able to work on cars at his age.
Thanks he loves it and is determined to show the car in early July at an event in Exeter at Powderham Castle. I take my hat off to him, and when he says thank you for the opportunity we've given him it does bring a smile.

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