About to drain coolant - Urgent advice needed

Technical questions and answers about the Mazda Bongo

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mikeonb4c
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About to drain coolant - Urgent advice needed

Post by mikeonb4c » Sun Mar 11, 2007 12:48 pm

Just reading me workshop manual prior to starting. Got a few (daft?) questions:

1) Manual says 'remove the under cover' but doesnt show what that is. Is it the plastic air duct that directs air into the oil cooler (it sites right underneath the radiator and obstructs view/access to radiator bottom so it woud make sense - it seems to have 3 bolts holding it on and maybe a couple of screws securing it to the next section of intake). Surely they cant mean the major under-cover that protects the sump etc - v difficult to do from underneath and not jacked up if so.

2) Which hose is the 'lower radiator hose' and they include a warning 'be careful not to get caught in the cooling fan'. Maybe it will be obvious when I remove the cover in (1) above?

3) There are 2 hoses at the radiator top. One is a bigger bore than the other. I dont know if it is important (the manual doesnt refer to it as needing checking for heat), but I ought to remove the correct one if I am backflushing oughn't I?

If anyone is reading this and can send a quick reply, I'd be really grateful.

Thanks as ever chums. I owe a lot of pints!

Mike

PS -about to read the changing the thermostat bit. I'll post any queries if I dont understand that bit! :shock:
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Post by mikeonb4c » Sun Mar 11, 2007 1:38 pm

Now trying to undo thermostat housing bolts. The one next to the oil dipstick (which obstructs it a bit) seems nigh on impossible to get at. Neither are easy. Anyone tackled this? I'll check previous threads as I think there is some avice ther, but if you are reading this and have any advice -YES PLEASE :lol:
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Post by mikeonb4c » Sun Mar 11, 2007 2:01 pm

SITREP - managed to get a purchase on the bolts, both loosened fine. Am proceeding towards target. Advice on (1) and (2) and on getting the plug out of the bleedin' bleed hose would be invaluable :lol: :lol:
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Post by mikeonb4c » Sun Mar 11, 2007 3:17 pm

SITREP - I've managed to get bolts off and thermostat out - hoorah. Also managed to get bleed pipe plug out - hoorah again! Everything, including colour of coolant, looks like it has just been done. Drat! Still, vendor said it hadnt been serviced in 2 years so had to do it so know where we are up to. I guess I'll backflush anyway out of interest, but does it need it if the coolant comes out a nice clear green? Reckon I've got a machine that has been well looked after. :lol:
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Post by bigdaddycain » Sun Mar 11, 2007 4:11 pm

Sounding promising mike. The fun bit is getting the bleed plug back in!I wouldn,t have thought that the backflushing was really essential if the coolant is so clean,but, if you hadn't of done it, you'd have wished you had afterwards....
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Post by bigdaddycain » Sun Mar 11, 2007 4:13 pm

Does SITREP mean situation report mike?
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Post by mikeonb4c » Sun Mar 11, 2007 5:11 pm

Yep bigdaddy, just me having fun again. To my great astonishment, I've managed to fit the thermostat, d the backflush etc. and I'm ready to refill with coolant. The water that came out when I backflushed was crystal clear, and the old thermostat looked so smart I had to keep it away from teh new one in case I got confused and put the old one back! So I think none of this really needed doing, but at least I now have the confidence that I know it didn't need doing (hey, I'm Irish OK). I've got a few tips and caveats for the next poor sod who is daft enough to try it - will write them up later. Just munching a sandwich then out to refill it, probably finishing after dark!

Mike :?
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Post by bigdaddycain » Sun Mar 11, 2007 5:19 pm

GULP! :shock: :shock: At least you KNOW its done eh mike? preventative maintenance is definitely the best cure for potential problems... It'll be worth all the effort :wink:
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Post by Peg leg Pete » Sun Mar 11, 2007 10:24 pm

I used an extension on a 1/4 drive socket wrench, undid bolts easily :wink:
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Post by mikeonb4c » Sun Mar 11, 2007 11:39 pm

Clever clogs Peter or - being Yorkshire - clever Cloggie :lol:

Well, I got it all done. I did use a socket and extension and it did the trick. I made life hard for myself by using a 6pt socket, as Dandy is quite right about the danger of burring bolt heads with a 12pt if they are tight. Trouble is, you are then limited by the number of positions you can get started with etc. Also, my metric socket set is limited and they are long sockets, which proved awkward. But Murphy's law prevailed and in the end, the bolts turned out not to be excessively tight. I also undid the dipstick tube bracket, which improved access to the more difficult of the two bolts. Part of it too was that - after many years of not working on vehicles - I tend to look at the job and think 'Thats impossible'. But by some miracle, it all works out. I used one of my Imperial 12pt sockets (which are shorter) to undo the bolts once the 6pt had done the initial loosening. And of course, putting them back on turned out to be no trouble after that. What else did I learn that might help the next poor bugger:

1) Couldnt get the bung out of the bleed tube. So, after squeezing the clip with pliers and moving it back, I carefully insinuated a watchmakers screwdriver down between the bung and the tube and then used a blowtorch to warm (but being very careful not to fry) the bleed tube. Whipped the screwdriver out and started twisting the bung while the rubber was soft and temporarily stretched. Had to repeat this a couple of times to extract the bung, but it worked a treat.

2) Thermostat - the workshop manual made me think I needed to separate the radiator pipe from the rigid pipe section that forms part of the lower thermostat housing. To remove this spring clip was nigh on impossible, let alone think how I would get the rubber pipe off in that confined space. So I didn't, and it didn't need removing! The housing could be manoeuvred fine with the rubber pipe attached. However, by this time I had managed using a g-clamp and a lot of patience, to slide the clip back. I then had to use a load more time and patience to get it back in place. A lot of wasted time, which you - dear reader - can avoid!!

3) The workshop manual mentions removing the lower cover, but doesn't explain what that is. The likely candidate seemed like the air scoop for the oil cooler and I started to take it off even though it didn't seem necessary in order to access the bottom hose (for feeling its temp. later on during the bleed process). It looked like it might be a nuisance to do, and time was against me, so I didn't do it. I still don't know why the manual says it is necessary.

4) The manual says something about removing a bung from a hose and draining old coolant from it. As time was short and the old coolant looked v clean, I didn't bother. Does it matter - anyone able to advise? Personally I doubt it is life threatening

5) I found the bleeding process (not being rude) quite scary. I found the workshop manual a little vague (for a beginner) on the precise sequence of leaving rad and header caps loosened etc. and - looking back - made the mistake of tightening the header tank cap after I had first filled it which was - I think - wrong. The next thing what confused me was that a pretty steady stream of coolant started to come out of the bleed tube once warm. This caused the level in the header tank to drop v quickly and I was worried I would reintroduce air into the system if it fell too far before I spotted it and could top it up. In the end - and despite concern over scalding myself - I hoiked the bleed tube aloft so coolant stopped running out and stuffed the bung in quickly, managing to avoid getting scalded. I'm sure this is not how it should be done though. By this time I had loosened the header tank cap and I let stuff gurgle back up into it for a while (it took a while) before I tightened the cap on it. The level still seemd to rise and fall a bit but eventually stabilised. I noticed earlier on that a little steam was coming from the radiator cap, which concerned me slightly. But the temp gauge never showed any sign of moving past 11.00 o'clock, and as the system settled down through what seemed and endless cycle of 5 mins at 2500rpm followed by 3 mins at idle, no more steam issued from the cap. So I think it is all settled in, and as I'll be doing short runs to work all week, there is plenty of opportunity to gauge watch and make sure all is well.

The above may seem long winded. But BF experts may be able to give advice that is useful to others (and me!) after reading the above, cos the coolant system really is like Chitty Chitty Bang Bang - very mysterious. Karen (Broxburn) has I think just done hers - how did your experience compare with the above Karen?

Anyway, its done and I'm sitting here drinking a cold beer and feeling mighty pleased with myself. The jobs to do list is getting shorter :lol: :lol:
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Post by Peg leg Pete » Sun Mar 11, 2007 11:43 pm

Mike did you get any hot air expelled from bleed pipe?
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Post by mikeonb4c » Sun Mar 11, 2007 11:53 pm

Yes I think it did although I wasnt stood over it so cant be certain. I certainly saw it spluttering as I rushed to and fro I think I left it plenty long so that in the end it must have been completely bled and just started to issue a stream of coolant. Problem then was I was losing coolant so fast I was under the bonnet replenishing rather than being able to watch the bleed tube. I noticed quite a lot of air bubbling back up into the header tank after I'd put the plug back in the bleed tube. The bottom hose heated up right on cue (10 mins exactly as per the manual) and the temp gauge never caused a moments worry. So although I didnt quite feel in control of what was going on, I felt overall that Mango had had a pretty good session of 'burping' and was probably thoroughly bled. I would imgine that if the gauge stays steady over the next week of local running, that ought to be it. What do you think?
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Post by Peg leg Pete » Sun Mar 11, 2007 11:58 pm

Did you back fill through the bleed pipe and squeeze all the hoses to dislodge trapped air. I have helped a fellow member bleed their coolant system today, and boy did the bleeder pipe burp out hot gas! Keep an eye on coolant level and of course temp guage, good luck :wink:
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Post by mikeonb4c » Mon Mar 12, 2007 12:18 am

Hmmmm no, nothing like that. I'll keep an eye on things. I presume it doesnt mean starting all over again does it? I mean the workshop manual doesnt say anything about backfilling the bleed pipe or squeezing all the hoses :cry:
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Post by dandywarhol » Mon Mar 12, 2007 7:14 pm

For future reference Mike - is there a cylinder block drain bolt on the engine?
I haven't got a manual (you beat me to it for the coffee stained one :wink: )
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