Overheating/coolant boiling after coolant change and bleed

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Long
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Overheating/coolant boiling after coolant change and bleed

Post by Long » Mon Jul 25, 2016 3:52 pm

Hi I am new to the Bongo Fury, I have a 1997 2.5 turbo diesel bongo. loved it until this problem, which is making me very stressed and confused about bongo coolant system.

I recently drained and changed my coolant. I also learned how to bleed the system with the hose under the passenger seat. I did it for about 2 hours. After completing the bongo runs fine, the next day completely cool the level in the header tank drops and i re-fill back to between low and full. I leave it for 1 week or more and the level stays exactly the same in the header tank.

however once i drive it for about 15-20 mins the coolant starts to boil and spills out of the header tank onto to floor and the car overheats. I pull over and let it cool right away. I thought i didn't bleed it properly, so i bleed it again for 3 hours this time. making sure there is no more bubbles coming out of the funnel to the point when i rev the engine the coolant come out of the funnel instead of sucking it in.

the lower radiator hose is hot and when heater is on the air is hot. However when left over night the next day it over heats again after 15-20 min drive.

by the way. BEFORE my coolant change everything was working perfectly. Very hot day AC on no over heating. So i am very confused as to why it is over heating now?

i used diesel long life coolant which is orange? the original coolant was green. does this make a difference? also what should i be looking at? this problem did not start until i changed the coolant so what part could be faulty? I also checked my oil, no signs of coolant in, little to no white smoke from exhaust? no coolant leaks and 0 drops in coolant level in header tank other than when it boils and spits out.

Do you have any suggestions on what part i should look at and replace?

1.Rad cap?
2.Thermostat?
3.Water pump?
4.Head gasket?
5.Coolant?
6.Fan?


Thank you very much for your help.
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g8dhe
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Re: Overheating/coolant boiling after coolant change and bleed

Post by g8dhe » Mon Jul 25, 2016 4:27 pm

OH I hope you thoroughly flushed the system!!!! See here http://www.autoblog.com/2009/12/28/coolant-color/
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Long
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Re: Overheating/coolant boiling after coolant change and bleed

Post by Long » Mon Jul 25, 2016 4:41 pm

Hi,

when i changed the coolant. I flushed it 3 time with distilled water until no green coolant was coming out under the radiator. Do you recommend re-flushing and changing back to green coolant?

thanks
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Re: Overheating/coolant boiling after coolant change and bleed

Post by g8dhe » Mon Jul 25, 2016 5:17 pm

Did you flush the radiator and the heating matrices forwards and backwards, they have lots of narrow pipes and get clogged with debris and coolant ?
Now that you have possibly mixed coolants, with gelling perhaps the result, your best bet would be to see if you can see any gel in the coolant, if so flush thoroughly again and take your pick of coolants.
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Re: Overheating/coolant boiling after coolant change and bleed

Post by Long » Mon Jul 25, 2016 5:34 pm

Hi g8dhe,

thanks for your help.I will thoroughly flush forward and backwards and switch back to the green coolant. Hope this works.
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Re: Overheating/coolant boiling after coolant change and bleed

Post by g8dhe » Mon Jul 25, 2016 5:50 pm

Lots of people use the long life red as it mixes with anything I believe ?
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Re: Overheating/coolant boiling after coolant change and bleed

Post by Long » Mon Jul 25, 2016 7:24 pm

I am able to buy global coolant which can be mixed with any colour coolant. Would this be the best choice? It is amber (red) they person at the store also said this coolant can mix with anything?

Will it have effect on boiling inside bongo?

Thanks.
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Re: Overheating/coolant boiling after coolant change and bleed

Post by Muzorewa » Mon Jul 25, 2016 7:31 pm

Are you sure you've bled it thoroughly? :?
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Re: Overheating/coolant boiling after coolant change and bleed

Post by Long » Mon Jul 25, 2016 8:22 pm

hi Muzorewa ,

I bleed it for 2+ hours. up and down with funnel on bleed hose under passenger seat. when reving the engine to 2000-2500 RPM in the beginning it sucks coolant in, then after 1.5 hours of bleeding the coolant in the funnel starts pushing out. i watched "how to bleed bongo" video and it says when it is pushing it out it is bleed completely.

I don't know how else to bleed it.

Thanks
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Re: Overheating/coolant boiling after coolant change and bleed

Post by Northern Bongolow » Mon Jul 25, 2016 9:04 pm

bleeding seems to progress better if the engine is not running at first, fill up as much as you can via firstly the rad then the expansion tank once filled have a good walk round the bongo and repeatedly squeeze as many hoses including the front and rear heater hoses the first hose out of the head and the front rad bottom hose back to the stat housing as you can, you can usually feel them move water about or hear the air being pushed around, try to work it out in a pattern remembering that air likes to sit above the water level till its pushed out.

then once happy you have removed as much as poss then switch the engine on to tickover, let it run gently and repeat the squeezing, then again when happy move on to the revving stage.

red coolant boils at a higher temp than blue/green so the type of coolant is more than likely not important at this stage. you must check that both the front and rear heaters (both in and out) are at the same temp, this says you have flow through them so are not air locked.

it is true that when the stat opens and the bottom hose is very hot that revving fills the funnel, where before hand revving emptied it.

it sounds to me like you need to manipulate the hoses before bleeding starts, this will help you later as simply revving the engine if its not pumping coolant does not bleed the air out.

hope this helps.
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Re: Overheating/coolant boiling after coolant change and bleed

Post by teenmal » Mon Jul 25, 2016 9:06 pm

Personally I would remove and test/renew the temperature control valve/thermostat , it might just be a coincidence that it has acted up after you carried out the previous work. You can actually check the cross flow in the radiator but unless you are confident with this procedure I would just test/renew.

How long have you had the vehicle?, if it is a recent purchase a Sniffer test might be in order.

This is presuming that All the Air has been removed from the system, any doubts I would go for a Vacuum drain and fill.
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Re: Overheating/coolant boiling after coolant change and bleed

Post by Long » Mon Jul 25, 2016 9:59 pm

Thank you very much for your response. I will try both mentioned methods. by re-flushing and also when bleeding squeezing the hoses to get air out.

the very strange thing is: right after i bleed the bongo, i go for a 30 min test drive. There was no sign of over heating during this test drive. it is only when the coolant is allowed to cool over night it overheats the next day. I am wondering if air is getting sucked in over night? When bleeding it I seal the system with the level right at full line. over night it drops and next morning it shows low. then i wait a week and the level does not drop at all. So this should mean no air got in and there is no leak.

does anyone have ideas why during the drive immediately after bleed is ok, but after letting it cool it and then starting it again it over heats?

thanks and much appreciated
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Re: Overheating/coolant boiling after coolant change and bleed

Post by cmm303 » Tue Jul 26, 2016 2:18 pm

Draining and flushing at the radiator defo does not thoroughly flush so if the orange coolant you put in first is of the non-mixable type then you will have got some reaction between the old and new.

A thought .... If the resulting precipitation in the coolant (I just know the chemists here are going to step in here to correct my terminology :oops: ) causes blockages as it cools could this cause the overheating on the next run? Also maybe it could have an effect on the thermostat and/or radiator performance?

I reckon the level drops about 1cm max in the de-gassing tank from hot after bleeding to cold. A drop from H to L seems a lot. I wonder .... either it is running very hot, loss of coolant during cooling, or gas/air in the coolant. Experts can get a feel for gas in the coolant by feeling the hoses - hopefully somebody will advise or try searching back through the forum. Bongobongo123 was taken through these hose-squeezing steps so his posts may help.

If you suspect you have grunge from mixing coolants I would reverse flush both front and back heaters as well as the rad.
As part of flushing I recommend you remove a pipe into the rear heater to facilitate flushing the fore-aft runs.
I'd also want to flush any grunge from the head through but not sure of the best way off hand.

Bleeding
Earlier posters have been my mentors on bleeding (though they may not know it!), and I recognise everything said. Definitely it is as much about filling the system methodically in the stages described before getting into revving. 2+ hours to do a single bleed seems a suspiciously long time if that is the time with the engine running. Was it very windy and hard to get the rad to warm up properly, or did it keep burping or bubbles just kept on appearing?
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Long
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Re: Overheating/coolant boiling after coolant change and bleed

Post by Long » Tue Jul 26, 2016 3:32 pm

Hi cmm303,

Thank you very much for your help. Im not sure why it was drop from full to Low over night. while bleeding the coolant is quite hot. the coolant also looks perfectly normal with no signs of gel or grunge. it is a slightly bit thicker/slimer when hot. When i was bleeding it was bubbling alot in the begining, then after about 1 hour of start stop reving, going up and down with funnel. it would be just very small bubbles and after 30 more mins. it would just be mirco bubbles from when the coolant filling the funnel. it did warm up normally in about 15 mins also when i turn on the heater it is really hot. However i was unable to get rear heat as hot. Rear heat was cooler air coming out. but this was the same case before i did my coolant change when the bongo was working fine.

I wanted to get your, and eveyones input on this:

I am thinking of draining the coolant as much as I can, I am unsure how to flush both heaters? if anyone can provide some quick instructions this would be greatly appreciated. I am able to take off the clamp of the rear coolant hose (driver side underneath) and let coolant drain from there and flush as well. after completely draining the system. I would seal everything back and then use a vaccum fill process. I checked on youtube these are quite easy to use, creating a vacuum in the system then filling it this way with a bucket of fresh coolant.

http://www.crookedriverwriter.com/index ... 9-air-lift

if i connected the device to my header tank, sucked the air out, and then filled it with coolant to the top. I will suck out the excess with a bulb and tube.(turkey baster) to make sure it is between low and full. Would this process solve my bleeding problem? does the vacuum cause any adverse effects to other parts of Bongo cooling system? also will the vacuum reach all the way to the back? Should the engine be running?

I have already bleed it 4 times and every time the coolant boils again. I just want to get all air out and leave no chance for error.

Thanks again for your help
Last edited by Long on Tue Jul 26, 2016 4:02 pm, edited 1 time in total.
Long
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Re: Overheating/coolant boiling after coolant change and bleed

Post by Long » Tue Jul 26, 2016 3:38 pm

Also i am planning to use Global antifreeze. This one can be mixed with any type of antifreeze. so it leaves no room for errors. any thoughts?

Thanks.