temperature rise and no heater

cliffy the climber · Post by **cliffy the climber** » Tue Jan 15, 2008 2:32 pm

thanks so far for the replies...
ive never topped it up..i had just come back from scotland(fort bill) the night before and all the way down no probs..
i do have other things that need doing but with the horrible weather of late i dont want to do them yet..ive already fitted an eberspacher heater..rebuilt the unit,reversed the seats and fitted a bolt on fiamma bike rack all during crap weather...
i have the squeaking from the old snapped off exhaust stud thing and i have trouble starting when cold..i.e.heater plugs...i was hoping to get a break from working on the bongo at least till the monsoon stops...!
maybe the coolant was low already and it got a gulp of air clutching at straws i know...
i cany see how a blockage can just appear..rad and heater matrix blockages usually occur when a vehicle has been stood and oxidation takes place as far as i am aware...
i will check out the factsheet on bleeding the system and see how it goes from there....

cliffy the still naffed off climber....

haydn callow · Post by **haydn callow** » Tue Jan 15, 2008 2:38 pm

good luck and do let us know the outcome. I think a Mason or TM2 temp alarm could have helped in this case.
Opps ! sorry no ad's

bigdaddycain · Post by **bigdaddycain** » Tue Jan 15, 2008 2:40 pm

The reason that bongo's are prone to airlocks isn't rocket science,all cars need to be bled after a coolant change,the bongo's problem is that its essentially "mid engined" with a lot of hoses,and a relatively complicated cooling system, this is further compounded with the twin heaters,the thermostat's rather high opening temperature is another issue.

You could sit there all day long with a bongo engine on tickover,and the stat may not open.

The uninitiated could in some cases fill the bongo up after a coolant change, then be suprised that it requires another 2-3 litres of coolant as the stat opens. (if the stat opens)

The bottom hose runs hotter when the stat is fully opened incidentally....

bigdaddycain · Post by **bigdaddycain** » Tue Jan 15, 2008 2:46 pm

Sorry Kirsty, i posted virtually the same as you had,we must have been typing the same thing at the same time, but you must type much quicker than myself (quite possible, im a one finger typist

)

cliffy the climber · Post by **cliffy the climber** » Tue Jan 15, 2008 3:15 pm

thanks bigdaddycain....
i was just thinking the same thing...its a complicated system with the heaters and being mid engined so to speak...i was just thinking how the syetem is kinda running on the edge really..to me at least, a machine or a system or even a part is either well on top of the job with room for error and problems that may occur with wear/time/age etc or it is just doing the job...it seems to me the bongo cooling system was designed to live life on the edge...
true all cars need the cooling system bleeding but it usually involves topping up the expansion tank and letting it tickover a bit and bobs yer uncle.....
i just hope its nothing serious and can be rectified easily...ive grown to love the bongo and drive it in preference to my other two vehicles even though it costs more to run...
im going to have a go at this bongo bleeding lark later......

cliffy the naffed off but thanks for the help guys climber

Socket Set Sue · Post by **Socket Set Sue** » Tue Jan 15, 2008 3:22 pm

I think if there was a leak in the cooling system this will cause an airlock.

The water pipe from just above the starter (under drivers seat) to the rear heater feed pipe has been known to have a pin hole which is very hard to see but over time will cause low coolant level and high temperature. You sometimes can only see this pinhole leak when the engine is up to temp.

I think it will be well worth while checking overall for coolant leaks.

Hope this helps.

haydn callow · Post by **haydn callow** » Tue Jan 15, 2008 3:31 pm

A pinprick hole in a hose (wherever it is) will cause coolant loss when under pressure. I'm not so sure this will result in a airlock, I doubt air would be sucked into a pinprick hole. However what could happen is that if the coolant loss is not noticed (you know what I'm going to say next) (not going to say it) and the level drops below the top pipe which exits the header tank, at this point air may well be introduced.

haydn callow · Post by **haydn callow** » Tue Jan 15, 2008 3:45 pm

cliffy....which method of bleeding do you intend to use.... I'm fairly well up on the see saw method having used it many times whilst working on the A**** S****M. If I can be of any help , contact me.

Socket Set Sue · Post by **Socket Set Sue** » Tue Jan 15, 2008 3:49 pm

I can' see why air should be admitted if the water level dropped below the top pipe which exits the header tank

If coolant is lost under pressure and air is not admitted to replace the coolant loss then you will have a vacuum in the system and an air lock could not be present under these circumstances. What could happen is the collapse of a rubber hose due to the vacuum. I think if water can escape then air can enter, thus casing the drop in coolant level and possibly an air lock.

BD - Thanks for confirming the bottom return pipe from the radiator will be hot when the thermostat opens and the coolant circulates, I have seen somewhere where it has been said the bottom pipe may get warm but not hot, mine is always hot to the touch during and after a run.

There is no complete answer to an overheating Bongo its just a matter of looking at the main points mentioned in this topic and searching the forum for ather posts.

Me - I would say, after a thorough top up and bleed, check for leaks, check for circulation (hot return pipe), if not maybe thermostat or blocked rad, check water pump for leak and drive belts.

Best of luck.

Veg_Ian · Post by **Veg_Ian** » Tue Jan 15, 2008 4:01 pm

A pinprick hole in a hose (wherever it is) will cause coolant loss when under pressure

Except that Cliffy is saying he is not experiencing coolant loss.

This assumes of course that he is also checking the level in the rad and not just the expansion tank..................

haydn callow · Post by **haydn callow** » Tue Jan 15, 2008 4:17 pm

The hose would only collapse when the engine is stopped and cooling down. I would think the reason it does this is because air is not being sucked in.
If enough coolant is lost and the level drops below the header tank in/out pipe coolant cannot go down this pipe. hence a airlock/void.
Anyway thats my thoughts and I offer them without any intention of rubbishing anyone else's suggestions.
It was (as you well know. Va*******k) me who suggested that a Bongo bottom hose should not get over HOT. After a good long run at resonable speeds/loads it should be possible to grip the said hose and keep it gripped.
I still stand by that and I have tested every Bongo that came my way.

haydn callow · Post by **haydn callow** » Tue Jan 15, 2008 4:20 pm

Ian, why would coolant be lost from the rad and not drop the level in the header tank to replace it?

Veg_Ian · Post by **Veg_Ian** » Tue Jan 15, 2008 4:28 pm

Haydn, it would if the vacuum was lost by a bad seal with the pipe between rad and expansion tank. Result would be coolant pushed out when hot but pulling back air when cooling down. This was a common fault on the Townace but admittedly not likely on the Bongo as the arrangement is more superior. I'm afraid I'm plucking at straws as everyone else because it doesn't make sense that the symptoms given aren't resulting in a coolant loss.

haydn callow · Post by **haydn callow** » Tue Jan 15, 2008 4:40 pm

I don't know this but I would think the townace does not have a pressurised header tank. This would make what you suggest likley.
However the bongo header is part of the cooling system rather than just a expansion tank. I tried to lose coolant from just about every conceivable part of the system and in every case the level in the tank dropped. However ..strangely ...after it had dropped about 1 to 1.5 inches under certain circumstances it stopped dropping in the tank and just kept pumping coolant out of the leak. This is why we had to put the alarm sensors just below the full line in the tank. We spent hours trying to put it in the tophose/rad/rad to header tank pipe all to no avail. It had to go into the tank.

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cliffy the climber · Post by **cliffy the climber** » Tue Jan 15, 2008 8:36 pm

thanks for all the replies...makes for interesting reading all this...
i had a go at bleeding the system with the see saw method(seemed the quickest) and both heaters were running hot..i checked the bleed pipe which was actually hanging over the exhaust manifold..! but could not find any leaks when the engine was at running temp...belts are ok..so i took it for a spin up a very steep long hill nearby...gassing it up the hill (something i would not normally do,i like to look after it) the temp stayed at 11 o clock and all the way home....
now it did the overheating thing and then it didnt before so i dont actually know whether i fixed anything or not...and it was on a short journey before so i dont think i need to go too far to test...i have yet to check the level in the expansion tank..i live on a hill and have to drive elsewhere to check oil/water levels...plus another bummer is the expansion tank is so discoloured you cant see the coolant...so its a dip the finger job...yep i know whats coming by now....!..so i will check the level later and see how it goes..if it does it again though im back to sqare one....maybe then i will check the thermostat as unlikely as it is....

while im on here although i have bigger fish to fry with this overheating lark..
i have noticed a bit of mildew type stuff in the free top..so after working on the bongo earlier i give it a wipe down with disinfectant and left the eberspacher on for a couple of hours..is there a common routine for sorting this...ive spent all my life camping so i know to air tents out and make sure they are absolutely dry before packing them up..but all it has done is rain...so no chance of this...any suggestions welcome..as the bongo gets slept in most weekends...

thanks again nice people....

temperature rise and no heater

Overheating

Coolant loss