V6 - running a bit hotter

[Simon Jones]

I've had the van off the road for a few weeks for Waxoyling in advance of LPG conversion. Took it out for run yesterday and noted that the temp gauge seemed to be running a bit warmer than before. With a Mason alarm, the gauge used to read between 12 and 1 o'clock, but is now between 1 and 2. Annoyingly, I didn't have my digital gauge connected up before I started the work, so don't have actual readings to compare. The changes that involve the coolant system were:

1) New Mazda 'stat which I tested in a pan of boiling water with the original one first. It opened at the same temperature and slightly wider.

2) Removed the rear heater matrix and bypassed it with a u-shaped pipe, ensuring no restriction in flow.



3) Refilled with new coolant and bled a couple of times to be on the safe side.

Other changes made, which should not have any effect include: oil and filter change, fuel filter change,
disconnect and blank off rear aircon, new spark plugs and I'll also be fitting new HT leads, rotor arm and distributer cap tomorrow.

The only change I've made that I would expect to change the characteristics of the system is the removal of the rear heater matrix. This would seem to have reduced the capacity by about 0.6 litre and reduced the size of the area capable of dispersing the heat. Overall, wouldn't have expected it to make any significant difference. For example, Wellhouse used to the remove the rear heater and fit a water tank on its place, so it's not an uncommon modification.

Any thoughts?

[jaylee]

Hi Simon,

Just to get the "ball rolling"... Was there any load on the electrical side of things?? Blower fan running/charging, that sort of thing....

The other idea... Though mine is a diesel.. I notice my Mason will do similar, then my gauge fitting for the top hose & heater outlet (2 channels) will rise by about 4 to 6 degrees, then the Mason will fall.. Not long after so will my gauge reading....



The first sensor to the top hose..




I'm sure you have nothing to worry about...!

[ajof]

My (inexperienced) mind would wonder whether the waxoyl has gotten on to something it shouldn't have and is effectively insulating it?

[Simon Jones]

That's a very good point. The van had only been started up a few times whilst it's been sat up on axle stands, so not really had a decent run to charge both batteries for about a month. I also had the headlamps and front blower on, so that would be a bit of extra load.

I've disconnected the lead to the A/C compressor to ensure it doesn't engage until I get it regassed. Also removed the rear seat, trim panel, carpet and conversion, so it probably weights at least 150 kg less. Goes like stink, but it's a heck of a lot noisier without all the stuff in the back to deaden the sound.

Another good point about the Waxoyl. Was very careful to mask everything off and keep it away from the radiator, etc. Got plenty of it on me, my clothes and someone else's driveway

[RobEvans]

Just a thought but removing the rear heater matrix would this cause the system to retain a bit of extra heat, as the matrix is like a radiator and even with no fans running will have a slight heat loss?

[Northern Bongolow]

maybe the stat is more efficient at doing what its supposed to do simon, keeping the temp of the engine at the optimum level, maybe it should be slightly hotter than it was running before, mpg may improve eh

[Simon Jones]

Took it out for a longer run today. Temp gauge still reading high, although the fans are not kicking in any more than normal, which I might have expected if it was actually running hotter than before. I'm going to take the 'stat out again tomorrow and compare it to the original one in a pan of boiling water. I'll probably stick the original one back again so I can eliminate one of the variables that has changed. Kicking myself for not having either my TM2 or Cube temperature gauges wired in before I started the work as I would have been able to tell for sure what the engine was doing.

I think I can eliminate the extra load theory now as the batteries are not fully charged and I didn't have headlights on. The brake discs had got pretty rusty after the van had been sat on axle stands without wheels for a few weeks, but they would have soon freed up after a few uses of the brakes.

[Northern Bongolow]

see if they close together simon, as well as open together.

[New Forest Terrier]

If this is any help I took the rear heater matrix out of circulation on my V6 last August due to a leak. There seems to have been no noticeable running temperature change at all.

After conversion to LPG last January I noticed a drop in running temperature by about two degrees. Not a lot but enough to be noticeable. I have a TM2 digital temperature gauge. My original one of these failed about a month after conversion and had to have a new module, but the drop was viseble on both TM2s.

[Simon Jones]

Thanks NFT, that's reassuring to know . Did you bypass with a loop of pipe, or block the existing pipe work?

I removed the brand new 'stat and tested along side the original one. As expected, the new one opened a little sooner, faster and closed later, however, I've put the original one in again just so I can eliminate that variable.

I also fixed a slight leak around the water manifold at the front of the block where the pipe from the heads goes to the top of the thermostat housing. I think this has probably been weeping since being disturbed to change the cambelt. Rest of the cooling system has been checked over and the coolant replaced last week came out perfectly clean so I'm confident everything is in very good condition. Also replaced HT leads, rotor arm, dizzy cap and plugs. Tomorrow will complete the bleeding process and check the timing.

[New Forest Terrier]

Bypassed with a loop of hose Simon.

I spotted coolant on the ground behind the drivers door and the level in the bottle was approaching low. There had been a small amount of coolant loss for the previous month and I was watching it carefully. A pressure test did not show up any leak and all hoses were fine. The rear heater matrix was bypassed as the most likely suspect and it has lost no water since. I never used the heater anyway so it was no loss.