Sniff test failure?

[Ritchie]

Hey guys Just returned from Cornwall,

Journey there no probs and first 2 hours back also fine untill i stopped for petrol then the Bongo threw out a load of water I presume from the overflow . Luckily I noticed let the engine cool and topped up water. But a mile later It overheated(I was prepared) and I stopped and called AA. Loads of tests and he said It failed Sniff test. (I take it this is serious i.e Head crack or gasket???) However 10 minutes later we drove 4 hours solid (if very nervous) with no problems whatsoever.
\
What do I do next?? (pretend nothing happened ??)

Help would be much appreciated

Ritchie

[Veg_Ian]

Get a second opinion from a garage I reckon. Better safe than sorry and all that.

[Aethelric]

Here's a theory:-
If your bongo is running hot under heavy load, then when you stopped for fuel and switched off the engine, then the cooling water stopped and the heat in the very hot engine may have caused localised boiling. This would push coolant out of the system. which would be replaced by air as soon as the steam condensed. When you topped up there was air in the engine which caused the second overheating but the air was pushed out and the system righted itself. I bet you went easier on the the rest of the trip, so that the bongo was not running as hot.
The sniff test failure is bad news, but have it done again. A roadside test is probably not as reliable as a garage test.
Dave

[mikeonb4c]

Here's a theory:-
If your bongo is running hot under heavy load, then when you stopped for fuel and switched off the engine, then the cooling water stopped and the heat in the very hot engine may have caused localised boiling. This would push coolant out of the system. which would be replaced by air as soon as the steam condensed. When you topped up there was air in the engine which caused the second overheating but the air was pushed out and the system righted itself. I bet you went easier on the the rest of the trip, so that the bongo was not running as hot.
The sniff test failure is bad news, but have it done again. A roadside test is probably not as reliable as a garage test.
Dave

Interesting point there Aethelric. I too have wondered if that big lump with no natural airflow over it could reach some unusual temperatures if worked hard and hot and then stopped up. Our old VW Polo used to let its radiator fan run on for a while after the engine had been turned off - why was that. I'm not enough of an engineer to know the answer to these questions though so can only wonder. But I do wonder if would do any harm to have the scavenger fan on more often than seems to be the case with the Bongo sensor (assuming the sensor is still working - its not easy to hear the scavenger fan even when it is on so who knows!)

[Aethelric]

I don't think the radiator fan or the scavenger would help much. If there was some way to keep the water circulating it would help. It's probably best to let the engine idle and for a while to keep the water circulating while the engine cools down, assuming the radiator fan works properly of course.
I guess an inoperative radiator fan would have the same effect as in the original post too.
Dave

[maxheadroom]

I used to have a SAAB 900 turbo when you went on a longish run is would throw a couple of pints of water out when you parked.
Never any problem with it apart from the time I holed a piston doing 124 on the M40, which being a turbo pressurized the crank case and blew all the oil out of the dipstick So apart from that no problems

[Ritchie]

Ok thanks guys,

Will have it checked out for peace of mind and keep an eye on it for a while.

Let me know if you have any more thoughts

Ritchie

[coco bongo]

Were you getting steam?(white smoke) prior to overheating.

[Ritchie]

No, no steam or white smoke. is that a good or a bad thing?

Ritchie

[westonwarrior]

No steam from the exhaust is a good thing

[coco bongo]

Steam was the symptoms of mine when my head went, also throwing the water out through the breather tube. If you have had no overheating problems so far, have the radiator flow tested, and flushed plenty to see if any real bad crud is in there.

Not sure if you are good at car mechanics or not, im no buff thats for sure. But get your garage to fully check the rad, if you have got £140 ish to spare, get another one, you wont regret it. And a thermostat is only about £20, so go through a little process of elimination. And also arm yourself with a copy of the bleed procedure fact sheet from the members area, to give your garage/mechanic.

As i say im no buff, but this is what i have experienced last year and my head went just before xmas .

Let us know how you get on

[francophile1947]

arm yourself with a copy of the bleed procedure fact sheet from the members area, to give your garage/mechanic.

He says he stopped for petrol - is the bleeding routine the same for the petrol engines?

[Ritchie]

Sorry John,

I have always had petrol cars before and forget to say Diesel when I refer to the Bongo

Ritchie

[bigdaddycain]

and I stopped and called AA. Loads of tests and he said It failed Sniff test. (I take it this is serious i.e Head crack or gasket???)

Hi Ritchie, if it failed a sniff test, then hydrocarbons are present in the coolant, which means the head gasket is leaking, (at the very least).

I'd have another sniff test done at a garage you can trust... If it fails again,seek the advice of the garage, chances are he'll say the cylinder head gasket is leaking,and will need replacement, hopefully the head is still ok,ask for them to pressure test it to be sure.

Got me fingers crossed for ya!

[Ritchie]

Thanks BDC

Spoke to my Garage today and they are going to do a sniff test again on Fri. All things point to Head gasket .
Will get it pressure tested but think it would have been more problematic if the head was cracked and don't think it would have driven 5 hours with no problems at all.



Just hope its going to be ok.

Ritchie