Bleeding questions

[Rhod]

I posted this query on my "Head Gasket - thoughts" thread, but then thought that I might be better using a different title!

"Well just had my first attempt at bleeding the Bongo, using the factory method...
All seemed to go well, except that I wasn't expecting coolant to start flowing from the bleed pipe quite so copiously Just as well I used a bucket for my collecting container. By the time I'd realised what was happening, panicked for a second or two, & raced into the house for the bottle of ready-mixed coolant (0 marks for preparation ), the reservoir was almost certainly empty. I topped the system up & finished the bleeding process. Temperature gauge behaving fine, heaters blowing nice hot air & I am left with the same amount of coolant left over as the extra that I added, if you follow me, so hopefully no air in the system. Or the same amount of air that I started with, of course.

Obviously I'm going to have to bleed the system again, just as soon as it's cooled down, to be sure however.

Questions:
1) Is it normal for coolant to flow so copiously once the engine heats up? Or is it symptomatic of a problem
2) After running the engine at 2500rpm for the requisite 6 minutes, plus a minute or so, the lower radiator hose was only slightly cooler than the upper one. i.e there really wasn't all that much difference in temperature. Bearing in mind that all this is done with a stationary vehicle & the Mason adjusted gauge didn't rise too far, is this unusual I expected a more significant difference. I heard the cooling fans come on, but am not sure which one since I was too busy running around between reservoir & temp gauge, muttering "Don't panic, Don't panic" to take time out to peer behind the radiator with a torch! Since both hoses were hot & the heaters were both hot I assume that coolant is flowing through the system ok
3) If I'm right in thinking that there are 2 cooling fans, plus the scavenger fan, where exactly is the second fan? I can see the one on the rear left-hand side of the radiator (looking from front) but can't spot the other amongst the shadows form torchlight."

Rhod

[Peg leg Pete]

There should be 2 fans behind the radiator Rhod, check again in daylight never used the factory method for bleeding, but the coolant will rush out of the bleed pipe with engine running and bung removed, not sure you need to rush and re-bleed the system, unless you are sure there is an airlock

[Rhod]

Thanks Pete - are the two fans side by side? I suppose removing the air intake might help me see!

In letting the reservoir run dry during the bleeding process I've effectively replicated what my "dodgy" mechanic did in the first place. The consensus from the forum was that I needed to bleed the system to ensure that no air got trapped, so I think that I'd better re-do it to be on the safe side. I've a 100 mile drive tomorrow, so best to get it right!

[dandywarhol]

All sounds about right Rhod - like Pete - I don't think you've got trapped air.

Once the 'stat has opened there's little difference in temperature between the top and bottom hoses - at least until the fans cut in to take away the heat.

Did you manage to get a sniff test done?

[Rhod]

Dandy/Pete
The level in the reservoir dropped by about 0.5l while I was bleeding the second time & was frothy - this was while the reservoir cap was still off - so I suspect that I had some trapped air.
The coolant that gushed from the bleed pipe first time around had some shinycopper coloured sediment - almost looked like copaslip, if you know what I mean. Would this be likely to be from the new radiator?

Haven't had a chance to get the sniff test done yet. I was over in Birnam for a meeting today - via work car. Heading back over to Perth tomorrow morning in the Bongo, & will see if I can get it done there. Is an MOT station likely to be my best bet for someone with the correct equipment.

I'll be off the forum until Sunday night.

Many thanks for your rapid advice. It's most reassuring to be able to tap into the wealth of knowledge on the forum so quickly.
Rhod

[dandywarhol]

An MOT 4 gas analyser would do it just fine.

[Rhod]

Thanks!

[Richard D]

The fan you can hear might be the bulkhead fan, yes there is two on the back of the radiator but also one under the bulkhead infront of the engine.

[bigdaddycain]

It sounds like you have done a sterling job my good man, be aware though that one could dislodge a small amount of crud from squeezing of the aforementioned hoses,that in itself wouldn't cause a huge issue, but please be aware that it could reduce the clarity of your fresh coolant somewhat. I would check the coolant levels daily, and have some pre-mixed coolant handy in the bongo as a cautionary measure, yip yip.

[Rhod]

Got the sniffer test done at an MOT station near my mums & it came out negative - so the head gasket is fine, as suspected

[mikeonb4c]

Got the sniffer test done at an MOT station near my mums & it came out negative - so the head gasket is fine, as suspected

Well thats good news

The hunt continues.....keep us posted and good luck

[dandywarhol]

[Peg leg Pete]

Good news