help!!!! coolant rises then gets too hot?? water pump??

[chipvan]

yippppppppppppppppppppppppppppppppppppppppe

Its cracked it,been on loads of test drives and alls great..thanks guys for your input owe you one!

[mikeWalsall]

yippppppppppppppppppppppppppppppppppppppppe

Its cracked it ..................

Follow most of the posts on the forum read bit and thought .... Bugga ..

[Northern Bongolow]

without reading all the thread again i am afraid that you havnt yet got to the trouble cause yet. i hope im wrong but it sounds like a leak somewhere,and by the sounds of it its low down below the head level.
the reason i say this are as follows.
you bleed it and its ok for a short time, park it up and leave it over night (no leaks of coolant) but air is sucking in a leak, then as you run the next day this air gets hot and dumps the coolant. or the air you havnt bled out goes to the highest point of the engine (head).
the cap could be the problem also as this allows air to enter the system whilst cooling down, this relaxes the system when at rest. the bottom face of the cap has a brass disc on the face, gently pull this disc out and make sure its moving ok.
i made a cap tester and over half tested fail to either hold the correct pressure (positive) or fail to let in enough whilst cooling (negative)
then get a pressure test done,just to be sure its air/watertight.

[chipvan]

Take your comment and thanks for the input,well its now been 24 hours since i fitted cap,and ive had no problem with coolant rise or overheating,ive done prob 50 miles round town,starting 1st thing this morning and just got in now...will keep an eye on things but all did seem ok after a new cap..

[chipvan]

Just for fun i could send you the old cap and maybe u could test it????

[Northern Bongolow]

see how you get on in the next few days, then pm me and we can test it.

[chipvan]

will do ,
and thanks iam taking in your advise...

[widdowson2008]

Agree with you Ady, although the symptoms chipvan was getting pointed to a faulty/insecure cap don't you think?
Reasons I suggested it in the first place was that:
1 - symptoms pointed that way
2 - it is a cheap AND easy thing to replace

[mentaliss]

[quote="chipvan"]hi guys,been having a spot of bother...
after changing a hose and fully bled the system using seesaw method with coolant on the max level in tank,the coolant rises to the top,

its fine when super cold and doing small trips.
____________________________________________________________
Just to satisfy my curiousity is this a diesel engined bongo

[chipvan]

Well to me i think it was the cap,48 hours later and a number of trips and no coolant loss or coolant rise...prob done 80 miles round town in 2 days.in my mind so far its fixed it

[chipvan]

Yes its a diesel

[Northern Bongolow]

i had one to look at over the last few days.
symptoms.
leaking rad and coolant loss, spotted by the low coolant alarm.

diagnosis.
that the stat and coolant were of unknown age so were contributing to a lack of control of temps. after a full strip including drain and examine the coolant, pressure test, which showed leaking rad but no other leaks.all rads were checked for full flow including the replacement one. stat replaced. fan switch tested and working well.old and new stat pan tested against a digital thermometer, the old one was a little lazy but still worked.
sorted----------bled up ------------wonderful job, or so i thought.
it was at this point that the owner said that as the seat was up they could now check the oil level .
guess what, non on the stick at all.

conclusion.
if you choose to run your bongo without oil it may attempt to boil. . it was only the bongo's ability to cope with the temps that stopped this happening. the temps had gone up but nothing untoward on the mazda standard gauge, the pressure had risen and popped the system at the weakest link,(the rad in this case but it could have been any hose or pump)
to be fair to the owner they are having a difficult time at the moment so have been distracted.

i also learned a lot, and that you MUST always find the reason why you have a leak, and not just fix the leak.

[chipvan]

good one..,i have a look at oil every couple of weeks....

found the leak ,and it was on the t peice that i have under the bongo that connects to my heatexchanger for my veg oil set up.Have had this b4,just needed a tweek on clip to stop leak.

I reckon that the coolant rise was where i opened the cap(not thinking ) when coolant was hot....then loads of air got in..

But the silly action that i did may have caused the cap to go up the spout as coolant and engine got hot(not over heated).. after a good bleed and a new cap all was ...and is so far ok.

But take what your saying here dont just top up and think all is good work out why it went in the 1st place!

[chipvan]

Did it again,this time tm2 got to 120 wife pulled over and left it down the road,so next stage presure test?? Hope head not cooked!

[haydn callow]

Your TM-2 is pre-set to alarm at 100C why on earth continue driving with the alarm sounding.,.???

And once you did stop the engine would continue to "heatsoak" another 5 to 10 C

I reckon that's well cooked