Mason alarm going off (part 2)

[campergeek]

I previously posted about my mason alarm going off here http://www.igmaynard.co.uk/bongo/forum/ ... =3&t=53298, and have since thought all was ok, but just had it going off this weekend, so would appreciate some opinions.

The temp gauge has been a bit higher than normal for the conditions, nothing critical, but enough to get me a bit paranoid. I had it serviced in january, and got them to have a thorough look at the cooling system and they gave it a clean bill of health. Anyway, this weekend I've done lots of very hilly driving, but also a-roads and motorways, and the gauge has consistently been higher than I'd expect. Took a couple of pics...

This is where the gauge is when it goes off...


And this seemed to be where it sat the rest of the time, mainly on flat a-roads and motorways...


This is definitely slightly higher than usual for these driving conditions. The gauge has never got much higher than the first pic, so don't think it's doing serious damage, but I'm concerned it's getting this high at 50/60mph on the motorway. Revs averaged about 2000, and even on hills didn't go much above 2500.

So, my concern is that it's not cooling as efficiently as it should. I could change the settings on the mason so the beeps don't go off and just live with it, but is this a sign of something more serious? I'm thinking the rad is possibly full of gunk, so not working as well as it should, but I'm open to other suggestions. The fact that it's getting this high on the motorway leads me to think I can rule out any issues with the fans/etc, which I think work as they should and definitely kick in with the AC running.

It may just be a case of me still learning to live with the quirks of my modded temp gauge, but I'd be interested to hear other's opinions.

Thanks,
Alex

[mikeonb4c]

I guess the big question is how do you know what to expect the first time you do some serious driving in hilly country. If the engine is working v hard and slower speeds reduce airflow through the rad, then the engine is likely to run a lot hotter. Other Mason owners have reported having to raise the trigger point after working the engine hard.

[triathlondave]

last year I went across to france. Big hills, well bigger tha UK

My gauge sat higher and every hill my Mason alarm went off. If anything just got worse and did not get lower.

Anyway when I got back I had a

New Radiator (MAZDA)
New pump
New Stat (MAZDA)
New Belts
rebleed and flush

Anyway the bit you want to know

The needle now sits below 1/2 way and only rises to middle now when pushing hard uphill. Alarm only goes off when going over hardsnott Pass in the lakes.

So If it's changed I'd look at a new radiator. talk to Haydon's he's a great guy to help you decide what's the right thing to do.

best wishes
david

[Northern Bongolow]

in my opinion you are right to be concerned, it looks like its running slightly high, especially when motorway driving, as long as your not thrashing it.

various things feed in heat though, is it a 4 wheel drive. what wheels and tyres have you on it. gearbox oil condition and level.

my money would be on the lazy stat,or copy stat, the coolant----is it old, the rad, the waterpump, and the temp sender. the fact that it doesnt cool on the motorway says a lot.

buy a digital temp measuring device, take some readings, this may point you to the right area.

[mikeonb4c]

Sorry,should have read your post more carefully. Ate your rad fans coming on a lot, as would suggest inefficient cooling. Any signs (rust stains in header tank or rusty coolant) that could point to a problem?

[triathlondave]

OH forgot

I put the heaters on full, when that brought the temp gauge down,

started to think I needed more radiator performance.

which is what helped me to decide to get a new radiator.

david

[teenmal]

Hi David,

Just as a matter of interest,what trigger position is the alarm set at.

Cheers.

[triathlondave]

I honestly can't remember!

I'm going to guess either 3.5 4. Set it low as I wanted to know when I had problems.

I need to take the dash off for the MOT (another story) so will have a look and get back to you be a week or so

david

[campergeek]

Northern bongolow - yes, it's 4wd. 4 new accelera tyres last year, probably done about 2k on them. Had ATF changed in the January service by ADS, who I trust know what tyre doing. It's an R reg, fresh import about 15 months ago. The coolant was also flushed at the service so should be new, though the header tank is stained - you can only just see the coolant level in good light. I absolutely don't thrash it what with the cost of diesel - as I say, it rarely goes over 2500rpm.

Dave - I haven't tried putting the heaters on full blast, but will give it a go next time and see how that affects it. So far I've just stuck the AC on to get the fans going, though this is probably pointless at 60mph on the motorway. Not even sure what happens with heating and AC on at the same time

Mike - I can't really tell if the fans are coming on/off when driving, though if the ac is on I hear them kicking in/out when stationary and the bonnet open.

So not really sure what to do next. If I install a digital temp gauge, I guess this will help me check if the stat is faulty. If it goes up and down in sync with the main temp gauge is it more likely to be the radiator?

The part for the stat is cheap enough, but is it a big job to replace? If not it might be worth doing for peace of mind before moving on to the rad, which is a bit more pricey. Probably not worth it if stat replacement involves a full bleed/flush though.

[wonkanoby]

you would have to bleed it after a stat change

[Simon Jones]

The good thing about the Mason alarm is that you can see when the 'stat opens as you will see the needle move up and then come back down again. Can you see this happening on yours? Changing the thermostat is probably a good starting point and is not too tricky to do. You'll need access from underneath and a decent socket set with a universal joint as one of the bolts is at a tricky angle. Alternatively, you can slacken of the dipstick tube and move it to one side. Also, get a genuine Mazda part rather than a copy. When the old one is removed, put them both in a pan of water and bring to the boil on the hob so you can see how the two compare. Typically, you will find the new one will open first and faster than the one you are replacing.

[Northern Bongolow]

most mason altered bongo's seem to like to run at about 4.5 this gives an alarm point just outside the normal running conditions, it will alarm at or around the fans on/off point, this is in my opinion for a good reason, if the fans are not working to cool the bongo you need to know, if they are working when they should the alarm simply goes off when the fans do their job.
from what you say i would say you have a copy part stat in place, and or a bad rad, best to do the stat first then see what happens, but ive seen normal rads give no problems, but when a new rad is fitted anyway this makes a massive impact on the temps seen at the gauge, so maybe worth doing that at the same time considering garage costs, both jobs in under 2 hours plus one bleed.

[campergeek]

The good thing about the Mason alarm is that you can see when the 'stat opens as you will see the needle move up and then come back down again.

I don't see the needle actually move about in a noticeable way. It more slowly creeps from one point to another. Does this mean the stat isn't opening? Any way I can check this?

[mikeonb4c]

Esp given evidence of staining in header tank, I wonder if a new rad (and themostat) should be seen as a good investment. I'll be interested to hear any observations you can make about when rad fans are coming on. It wouldn't cost that much extra to fit a new water pump as part of the overhaul, as pump efficiency often gets left out of these discussions. Mind you, maybe a Mazda part should be trusted to keep working properly. What's your mileage btw?

[campergeek]

Hi Mike. It's just coming up to 100k km's. Supposedly genuine mileage, but who knows really.

Need to do a bit of research on rads. The shop has a copy one that's a lot cheaper than the mazda one. I know some copies are dubious, but will do some reading up on this one.