coolant leak mystery
Page 1 of 1

Author:  smurf182 [ Thu Apr 05, 2018 12:14 pm ]
Post subject:  coolant leak mystery

Got home from work this morning after a short run of the mill 5mile journey. No issues, no problems and parked on the drive. Popped the bonnet as its the first decent day since getting the car and thought id poke about a you do.
Then I noticed a big puddle of crap looking coolant and the drive, not good. No obvious signs of leaks from any of the hoses, radiator, bottom (of completely empty) expansion tank.
Topped up with fresh coolant, turned car over to see if a running engine soul pressurise the system and reveal a leak but nothing.

Any ideas anyone? One thing I did notice was the small finger width depression on the top of the gearbox was full of old rusty coolant. Oil cap off, no sign of the dreaded mayonnaise.


Author:  pitrack_1 [ Thu Apr 05, 2018 3:43 pm ]
Post subject:  Re: coolant leak mystery

One suggestion is to change the radiator cap. Rusty radiator coolant means the radiator cap has probably corroded as well and the pressure relief may be getting stuck. This results in the next weakest point relieving the pressure- probably a hose clamp/joint. Once the excess pressure is relieved, it self-seals and as the pressure turns to vaccuum as it cools, the radiator cap works and the system sucks the expansion tank dry. Hey presto! Puddle on the floor, empty expansion tank and no obvious leak.

Happened to me with my old N13 Pulsar. The solution is DON'T CHANGE THE RADIATOR CAP...YET. Fill the expansion tank, get it to operating temp and let the car idle & watch what happens as the temp rises. If in doubt, turn the engine off when the fans start, you'll hear the hiss of escaping coolant and probably see the steam and be able to trace it that way (note the thermostat needs to be working properly too). If not, there's another issue! Once sorted, drain, flush, refill and fit new radiator cap (when cool).


Author:  brucey76 [ Thu Apr 05, 2018 9:02 pm ]
Post subject:  Re: coolant leak mystery

OK not 100% on the 1500 but on the v6's theres coolant hoses running to the throttle body and under pressure they can leak straight onto the gearbox. I've never had a 1500 but if the throttle body is around there it'd be the 1st place I'd check

Author:  maZZda [ Thu Apr 05, 2018 10:43 pm ]
Post subject:  Re: coolant leak mystery

TB is a little further back(above the starter)
I can point something else, try to see if the coolant hoses to the cabin heating radiator are in good condition and especially look for the plastic adapters that the hose connects to.Mine was cracked and it was leaking above the catalityc converter..
Another thing, make sure that the valve on the rad cap is working correctly and opens above 0.9 bars...
If not it could make the mess you saw.. :)
And if it over-pressured the system it could lead to cracked plastics on the rad..(ask me how i know :cry: )

Author:  smurf182 [ Thu Apr 05, 2018 11:25 pm ]
Post subject:  Re: coolant leak mystery

Cheers for the pointers guys, turned out to be a tiny nick in the top hose just where it connects with the engine, managed to grab the top hose off womble and its in good condition. Will be swapping ut over as soon as the coolant cools down enough so I don't scald myself.

Page 1 of 1 All times are UTC [ DST ]
Powered by phpBB® Forum Software © phpBB Group