bongo overheating

[bongo al]

Hi All. Just joined. Enjoying our Bongo a lot, but much less so this month due to weird cooling problems. Last 6 months have seen intermittent problems, all traceable to broken clips or perished hoses. Latest incident more worrying. 2 weeks ago, replaced a hose (the one over the starter) Car used for about 1 week, then noticed drop in coolant level. Topped up header tank and ordered new hoses. I decided I may as well replace the lot. Vehicle is used daily, so i have been keeping an eye on the coolant level. Checked yesterday, and seemed ok. Drove about 40 miles to town and back on various errands, and it started to get hot. Stopped and checked. Carefully loosened cap on header tank, but it started to blow hot water out of the vent pipe so i quickly sdrewed it tight again. Let it cool down and limped home in short stages. Today tried everything to get coolant in. Carefuly bled air from vent pipe under passenger seat as i topped up header. Started engine and as it warmed up, rad fans seemed to come on slow then fast then scavenge fan came on. Rad was cold, as were top and bottom hoses. Took bung out of bleed pipe, with accompanying jet of steam. Replaced bung and topped up. Ran engine again. Checked header tank. System pressurised. Undoing cap a little let coolant out of overflow pipe. Switched off. Took bung out of bleed pipe and vented. Replaced bung. Topped up header tank. Repeated this whole process for 2 hours. Still gets hot, fans come on but rad is cold. Stat was replaced 6 weeks ago with new unit.

Sorry to bang on, but hope details clear. Also apologies if already covered here before. Please help

[francophile1947]

Sounds like you've either got an air lock, preventing the coolant from circulating, or a broken water pump.
You should have the bung out of the bleed pipe, for all the time when the engine is running, to expel all the air.

[Eat Aunt]

Hi All. Just joined. Enjoying our Bongo a lot, but much less so this month due to weird cooling problems. Last 6 months have seen intermittent problems, all traceable to broken clips or perished hoses. Latest incident more worrying. 2 weeks ago, replaced a hose (the one over the starter) Car used for about 1 week, then noticed drop in coolant level. Topped up header tank and ordered new hoses. I decided I may as well replace the lot. Vehicle is used daily, so i have been keeping an eye on the coolant level. Checked yesterday, and seemed ok. Drove about 40 miles to town and back on various errands, and it started to get hot. Stopped and checked. Carefully loosened cap on header tank, but it started to blow hot water out of the vent pipe so i quickly sdrewed it tight again. Let it cool down and limped home in short stages. Today tried everything to get coolant in. Carefuly bled air from vent pipe under passenger seat as i topped up header. Started engine and as it warmed up, rad fans seemed to come on slow then fast then scavenge fan came on. Rad was cold, as were top and bottom hoses. Took bung out of bleed pipe, with accompanying jet of steam. Replaced bung and topped up. Ran engine again. Checked header tank. System pressurised. Undoing cap a little let coolant out of overflow pipe. Switched off. Took bung out of bleed pipe and vented. Replaced bung. Topped up header tank. Repeated this whole process for 2 hours. Still gets hot, fans come on but rad is cold. Stat was replaced 6 weeks ago with new unit.

Sorry to bang on, but hope details clear. Also apologies if already covered here before. Please help

Try sending 'Aunt Trumpet' a pm. He was going through same probs , but seems to have nearly solved it

As francophile above says keep bung out of bleed pipe as you run engine. (needs to be run at 2500 rpm for approx 5 mins to enable thermostat to open.) Keep end of bleed pipe above level of header tank.

Possible you may have a bad case of trapped air so to speak (fingers crossed thats all it is )

[foofighter]

hi sorry to hear of your problems

did you drain the system before you " tried to get cooland in "

do a search on sea saw bleeding or look at the fact sheet in members area

[bongo al]

Thanks for prompt responses. New water pump fitted last month due to failed seal. I left bung out with engine running for at least 15 minutes while topping up the header tank with a hosepipe. Will try the see saw method OP recommended and get back

Once again many thanks

Regards

Al

[haydn callow]

Thanks for prompt responses. New water pump fitted last month due to failed seal. I left bung out with engine running for at least 15 minutes while topping up the header tank with a hosepipe. Will try the see saw method OP recommended and get back

Once again many thanks

Regards

Al

'fraid that won't work...putting water in as you let it out will not let the coolant get up to temp and the stat open....You must get the stat open or your bottom hose could be full of air.


NOTE.. (Before you start) Get a large funnel and cut the spout so the bleed tube will push up into it nice and tight.. Don't take the bung out of the pipe yet.

1..remove the plastic air scoop from under the bonnet.
2..remove the pressure cap off the expansion tank.
3..remove the pressure cap from the rad and fill to brim if it is not already full.
4..replace rad cap.
5..fill the expansion tank to the FULL line.
6..release the rad cap till coolant overflows and tighten rad cap.
7..top up expansion tank to FULL
8..under the passenger seat ..find the coolant bleed tube...remove the bung and push up into funnel.
9..half fill the funnel with premixed coolant.

Note..by raising/lowering the funnel you will from now on be able to control the level of the coolant in the header tank & funnel.
At no point from now on allow the funnel to empty or the header tank to drop below FILL.

10..start the engine...switch on heaters.....rev to 2500 for 3 mins....idle for 1 min.
11..keep repeating this cycle until the heaters blow hot and switch the heaters off.
12..carry on with the rev 2500/idle cycle..raising and lowering the funnel...you will have to do this for about 30/40 mins.....UNTILL THE BOTTOM HOSE GETS GOOD AND WARM..(stat open).

Once this happens carry on till all bubbles stop and replace the bleed tube bung (wear gloves..very hot)put the bung in as coolant is flowing out so no air can sneak in.

Top up the tank...replace the tank cap.....go for a drive and keep a eye on coolant levels for a few days....should be o.k. If job was done properly.

THE SECRET IS TO GET THE BOTTOM HOSE HOT WHILST BLEEDING (STAT OPEN)

ANY PROBLEMS PHONE ME 01458 270230 AND ASK FOR HAYDN

[bongo al]

Hi Guys. Back again, I am sorry to say. I have been busy trying Haydn's suggestion. I used an old 4 pint plastic milk container, and drilled a amall hose in the lid to take the bleed hose, and cut an opening in the base to add coolant. I used Haydn's method as above, and had some success. This time the radiator top hose got hot, and the front heater began to work, but despite trying for over an hour, the bottom hose only became lukewarm at best. Towards the end it appeared to me i was getting steam, not air in my milk bottle 'funnel', which made the water boil violently. Anyway, after my labours, I left it all connected while it cooled down. About an hour ago, I went out to put it back together. Coolant levels in both the header tank and the 'funnel' were fine, so i refixed the bung, taking care not to allow any air into the pipe. Then i took it for a test drive. (actually up and down the road - i did not want to go too far from home. After only an estimated 4 - 5 miles, the fans were on and the needle was at 1.00 o'clock. Parked it up and checked under the bonnet to see coolant spilling from the vent pipe on the header tank. Seems I am back to square one. Any ideas as to the cause?
Regards

Al

[francophile1947]

Might be worth replacing the cap. If it's not that, I'm afraid it looks like the head gasket and/or head has gone

[haydn callow]

I'm wondering if your new stat is working as it should.

[bongo al]

Hi Haydn

Many thanks for your help the other day on the phone. I was puzzled by the top hose getting hot, but not the bottom one. Seemed that coolant was not flowing as it should. I am also thinking maybe a stuck stat or blocked radiator. Will get these checked out.

Regards

Al

[Aunt Trumpet]

Mate, I've had very similar problems. I replaced my stat the other day because it seemed to be a very long time before the bottom hose got hot. In fact it would sit there for easily half an hour and the fans would come on, gauge (not reliable) would sit at normal and it would still stay cool. I even took it for a run down the road...nearly overheated it again, stopped in a garage and it was cool. That was pretty much the excuse I needed so I got another.....£15 from the local motor factors.

I tested both in a glass jug with boiling water and although the old one did open it was definitely slower than the new one. I read that you have had a new one recently though? strange, why not take it out altogether and see i it makes a difference?

With the bleeding process, I got the help of a mate to help top the fluid up as described above, however before we started up the engine I held the bleed pipe above the level of the header tank and he blew down the header tank until water came out of the bleed pipe, pressurising the system. When there was a steady stream I put the bung back in. Does that make sense?

We then got the engine up to temperature all we did was release the bung several times until a steady stream was seen again . The first couple of times we had a mixture of bubbles and coolant but after a couple of revving cycles it maintained a steady stream indicating no air.

The day before I didnt have any help so I balanced my socket set on the accelerator pedal which brought the revs up to around 2500 and if you shut the passenger door with the window down the bend in the bleed pipe fits nicely through the window and hangs on the door, pointing outwards. Its also just above the header tank.

Not sure if this is any help but if you get stuck PM me and I'll send my mobile number and I'll try and explain in person......good luck.

[bongo al]

Just back with an update. Took the rad off and had it flow tested by a local specialist. Good news - the rad is fine. Bad news - it must be something else!

The local garage say they can test the head gasket by analysing the exhaust for excessive water. Obviously some water is a combustion by product but they say they can tell the difference. After that will try running with no stat and see what happens.

Will let you know

Al

[bongo al]

Back again with just a thought!

Talking to the man at the local motor factors, it seems that many years ago stats came with a small built in bypass valve. Sadly this feature has all but disappeared in the interests of manufacturing economy.

From his description, it sounded like just what i need to make sure no air is trapped in the hose behind the stat. Any one heard of anything similar?

Regards

Al

[haydn callow]

Lots of stats have a "Jiggle pin" built in but if you bleed the Bongo properly ...i.e...get the bottom hose hot and the stat open then it dosn't really matter..
Make sure your stat is working and go from there

[missfixit70]

Pretty sure my stat's got one of those.