Overheating - Looking for troubleshooting steps

Technical questions and answers about the Mazda Bongo

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mikeonb4c
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Re: Overheating - Looking for troubleshooting steps

Post by mikeonb4c » Sun Sep 15, 2019 11:06 am

The oil around the diesel pump should only be diesel fuel oil which has no connection with coolant system. Also, I've not heard of a Bongo gasket/head problem that results in coolant in engine oil system. As a rule I think the consequence is cylinder pressure forcing gases into the coolant stream (hence hoses getting hard very soon after start-up). Regarding UV dye etc I seem to recall doing similar when my head gasket / head was suspect and finding it hard to get a definitive result (I was trying to see if any coolant was exiting exhaust tailpipe and leaving a dye residue there (i had excess water vapour exiting there which, along with slight coolant loss and slight lumpy start, were arousing my suspicions). In the end, with mine, I just had to decide the evidence was strong enough to have the head stripped and find out. And it turned out it was the right decision as the head turned out to have a hairline crack. New head 3yrs ago and running great since. I'd had a new radiator about a year before that as it had split near the top and looking back I do wonder if an element of over-pressurisation could have triggered that though I've heard many case of an old Bongo radiator going so maybe thats just an age thing. The long and short of it I found myself thinking, is given the years of great service and reliability, changing key elements like radiator, thermostat, engine temp sensor (which got broken anyway during head replacement), maybe water pump though I think they're less of an issue, was not a bad spend of cash while the head was anyway having to be done. A lot of modern cars can easily throw bills of that size anyway. But it still stings at the time, and it doesnt stop money needing to be spent on welding!
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Re: Overheating - Looking for troubleshooting steps

Post by surfkernow » Sun Sep 15, 2019 12:20 pm

Hi Mike , thanks for the detailed reply. I was going to have another go at bleeding the system today, i turned the Van on but there was a lot of stuttering and now white smoke billowing out of the exhaust, which is a new development and another indicator of a gasket problem. I have this morning resigned myself to have my Bongo put on the back of a lorry and taken to a Bongo specialist.

I will have to wait for a diagnosis but if it is the head gasket and potentially the cylinder head, i will have to consider a repair or a full engine swap. I have only had the Van for 4/5 months and there was no real history with it. But, that will be a decision further up the road. Thank you for your help. I will update the post in a week or so when I get a diagnosis.
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Re: Overheating - Looking for troubleshooting steps

Post by mikeonb4c » Sun Sep 15, 2019 7:13 pm

They should give you an expert considered view on what the best thing to do is (for example, it will cost x £s to fix the immediate problem, but what other costs might be coming up - rust for example - as you have to take a view on how much / long term you want to keep the Bongo and what investment you're prepared to make for that). Good luck getting it sorted and keep up posted.
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Re: Overheating - Looking for troubleshooting steps

Post by surfkernow » Mon Sep 16, 2019 3:20 pm

Hi Mike, thank you for the reply. I will of course keep you updated, albeit it might be a week until I have a diagnosis. The garage and I chatted over messenger yesterday and he is back at work tomorrow so I will have a better idea soon. Just looking at recovery trucks as we speak, it is an 80 mile journey so not close, but not too far :)
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Re: Overheating - Looking for troubleshooting steps

Post by mikeonb4c » Mon Sep 16, 2019 3:57 pm

surfkernow wrote: Mon Sep 16, 2019 3:20 pm Hi Mike, thank you for the reply. I will of course keep you updated, albeit it might be a week until I have a diagnosis. The garage and I chatted over messenger yesterday and he is back at work tomorrow so I will have a better idea soon. Just looking at recovery trucks as we speak. :)
Depending on where you are there could be others. Discount Trucks at Newbury come to mind as an example :roll:
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Re: Overheating - Looking for troubleshooting steps

Post by Bob » Mon Sep 16, 2019 4:10 pm

There's a recommended garage near Bodmin, too.

Sorry, can't think of the name. :oops:
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Re: Overheating - Looking for troubleshooting steps

Post by surfkernow » Mon Sep 16, 2019 5:47 pm

Thank you Bob and Mike. I am located near Land's End in Cornwall; it is ok, I will speak to the garage tomorrow and hopefully have my van shipped to them this week. I will keep you updated, albeit there might be a small wait until there's a diagnosis.

I have only owned the Van for 4 months, but there's one positive...the Van was due to go in for Welding next week. If I had spent a load of money on welding and then this happened...i think it would of broken me :)
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Re: Overheating - Looking for troubleshooting steps

Post by mikeonb4c » Tue Sep 17, 2019 8:27 am

Bob wrote: Mon Sep 16, 2019 4:10 pm There's a recommended garage near Bodmin, too.

Sorry, can't think of the name. :oops:
Pitstop Motors is it? But clearly, Discount is not nearer!
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Re: Overheating - Looking for troubleshooting steps

Post by mikeonb4c » Tue Sep 17, 2019 8:31 am

surfkernow wrote: Mon Sep 16, 2019 5:47 pm Thank you Bob and Mike. I am located near Land's End in Cornwall; it is ok, I will speak to the garage tomorrow and hopefully have my van shipped to them this week. I will keep you updated, albeit there might be a small wait until there's a diagnosis.

I have only owned the Van for 4 months, but there's one positive...the Van was due to go in for Welding next week. If I had spent a load of money on welding and then this happened...i think it would of broken me :)
Hopefully the garage will give a straight talking view on the whole situation. Bummer, but these are old cars and will inevitably need some investment sooner or later. About to spend on more welding for mine, new head etc was 3 years ago so have walked those roads but has been well worth it for 13 years of unique usefulness and fun and overall no more (and probably less) cost than most cars.
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Re: Overheating - Looking for troubleshooting steps

Post by surfkernow » Tue Sep 24, 2019 12:45 pm

She is on her way to the garage. I will update in a few days/week when I the problem is confirmed as I will probably canvass views on the next best steps. Cheers

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Re: Overheating - Looking for troubleshooting steps

Post by surfkernow » Sun Sep 29, 2019 3:15 pm

Garage has examined my Bongo and the initial diagnosis is :

1) The system did not over-pressurise when tested and the cylinder head temperature was 86/88 degrees which was fine

2) There is a coolant leak on the water elbow 'above' the diesel pump. Its dripped coolant onto the pump. Which explains why I saw the dye dripping from the pump

3) The Diesel Pump is also leaking Diesel

4) The water pump appears to be/have leaked

As garage stated, all of these leaks could have drawn air into the system and caused the symptoms I saw. As he pointed out that Cylinder head could have been weakened by the overheating and it could go in a few months or might be fine for ever. That's the risk element. My instinct is, that if it is not broken yet, not to fix. Purely from a cost perspective as the cylinder head and labor would be the the most costly part.

But, as garage pointed out, until the water pump, elbow and thermostat are changed he won't know if it will bleed correctly. That's just an update for those who have replied to my thread :)
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Re: Overheating - Looking for troubleshooting steps

Post by Northern Bongolow » Sun Sep 29, 2019 3:42 pm

From the pics on page 1 it looks like the rad is non standard, it looks like it has a metal top tank instead of plastic, it also looks like it has had a bleed / fill valve fitted to the top of the tank. This may indicate issues bleeding in the past, but I'm sure they will have it in hand.
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Re: Overheating - Looking for troubleshooting steps

Post by surfkernow » Sun Sep 29, 2019 4:02 pm

Hi Northern Bongolow, I did not know that regarding my radiator. I did notice it had a pressure relief valve on it. Maybe I should swap out the radiator as well?
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Re: Overheating - Looking for troubleshooting steps

Post by Northern Bongolow » Sun Sep 29, 2019 7:22 pm

Is that what it is?. It's non standard whatever it is. Just highlight it to garage in case.
It shouldn't need a pressure relief valve, especially so low down on the system as it should already have one in the correct position, at the highest point, built into the expansion tank cap.
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Re: Overheating - Looking for troubleshooting steps

Post by mikeonb4c » Sun Sep 29, 2019 9:45 pm

surfkernow wrote: Sun Sep 29, 2019 3:15 pm Garage has examined my Bongo and the initial diagnosis is :

1) The system did not over-pressurise when tested and the cylinder head temperature was 86/88 degrees which was fine

2) There is a coolant leak on the water elbow 'above' the diesel pump. Its dripped coolant onto the pump. Which explains why I saw the dye dripping from the pump

3) The Diesel Pump is also leaking Diesel

4) The water pump appears to be/have leaked

As garage stated, all of these leaks could have drawn air into the system and caused the symptoms I saw. As he pointed out that Cylinder head could have been weakened by the overheating and it could go in a few months or might be fine for ever. That's the risk element. My instinct is, that if it is not broken yet, not to fix. Purely from a cost perspective as the cylinder head and labor would be the the most costly part.

But, as garage pointed out, until the water pump, elbow and thermostat are changed he won't know if it will bleed correctly. That's just an update for those who have replied to my thread :)
Sounds like a very fair assessment from the garage. Fingers crossed it works out not too dear! Good luck & keep us posted. [-o<
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