DIY Car Maintenance with function over finesse!!

[CitroJim]

That was a superb day out yesterday Mick and despite the jams, hugely enjoyed it Thank you!

Delighted the Mazda's woes are just a duff indication on the gauge and nothing serious - result

[mickthemaverick]

Well today's post was supposed to be a follow up on the MX3 temperature sensor but when I got up this morning it was pouring so I don't like taking the cover off when it's wet and hence decided to head to Radlett for breakfast. I parallel parked outside the cafe,nudging the kerb as I did so, and enjoyed a great brekkie. Left the cafe and couldn't believe it when just 150m down the road I felt the same wobble I had felt on the North Circular on Wednesday. I was driving up a narrow road with lines of cars both sides so I had to keep going 30m to find an entrance to a gated apartment complex which I happily parked across out of the line of trafic allowing normal use for all bar those residents. The 10 minutes I had taken on Wednesday was cut down to 7 minutes, spurred on by the rain, and then I dropped my friend off and headed back to my tyre man arriving like this:

MTMO

Peter examined the tyre, which I thought I may have popped off when I caught the kerb, but no, for the second time in 4 days I had a conventional puncture with a large flint through the centre of the tread!! Peter immediately replaced the tyre and rebalanced the wheel for no charge, I gave him a tenner

So now back at home waiting to test my overnight theory that the temp guage issue in the MX3 is down to a build up of grime on the surface of the sensor which is the single wire type. Hence accumulated muck spanning the gap from block to spade terminal may be causing a partial shunt of the thermister. We'll see when it stops raining, but I've ordered a new sensor anyway!!

[CitroJim]

Oh gosh Mick, that's a bit of terribly bad luck with the tyres

[mickthemaverick]

So now back at home waiting to test my overnight theory that the temp guage issue in the MX3 is down to a build up of grime on the surface of the sensor which is the single wire type. Hence accumulated muck spanning the gap from block to spade terminal may be causing a partial shunt of the thermister. We'll see when it stops raining, but I've ordered a new sensor anyway!!

This morning in the break in the rain I decided to check out that theory. I put the car in the garage in case and opened the bonnet to examine the temperature sensor plug:

Not good, theory still alive!

I then pulled the connector off and examined it:

Not at all good, theory still alive!

I looked at the sensor still in the block:

Even worse, theory looking valid!

So I cleaned it all and reconnected it:

Fingers crossed!!

Having refitted the sensor I started the engine and let it run until the fan came on. I took the temperature readings as before and all was good! I got in the car and looked at the guage and it was just below red, theory destroyed!!

So the new sensor should be here in the next couple of days so for the next installment of this exciting story watch this space!!

[PaulC5]

Before you fit the new sensor, plug it in to see if the gauge is then normal. You could also look at live data. Just helps to confirm the sensor and not a wiring or other problem before going to the bother of fitting it. You could even put it in hot water or warm with a hair dryer.

[mickthemaverick]

Thanks Paul, you have read my mind. I'll be taking some resistance readings in my pan on the hob, both the new one and the old one when removed. I am doing it 'on the fly' without draining the system . I have a set of rubber bungs and I intend to remove old sensor, immediately insert bung to spill minimum coolant then do the testing before refitting. Working on a cold engine of course.
I may attach an earth connected pot to the lead and adjust while watching the guage and hence discover the resistance at 'normal' to see how that compares with the sensor on test at 95°C. Or I may not

[mickthemaverick]

Well the new sensor arrived this morning:

Nice and shiny!

so it was an opportune time to do the testing. The new sensor ranged from 760 ohms when cold to 120 ohms in a boiling pan. I swapped them over and tested the old sensor 1Kohm when cold down to 110 ohms in the pan. Hmmm!!

So I ran the engine up to 'fan on' temperature and watched the guage with the new sensor fitted, damn it!!! The needle stayed around normal but then began to intermittantly shoot off the scale and drop back to normal Grrrr! I double checked the wiring loom to be sure there was no intermittant earth and then connected the meter across the live sensor and sure enough it was giving intermittant full short circuit pulses Grrrrrrr!! I refitted the old sensor after a further clean and topped up and bled the system with my funnel method and it settled down to run for 45 minutes with the fan switching on and off and the guage representing that by climbing from the horizontal about 4 mins on a clock face to fan on and then dropping back to normal as the fan took effect. So maybe the problem was more ingrained muck in the sensor than I cleaned the first time but at the moment it all looks good!!

[CitroJim]

You fell victim to Joe Lucas the Prince of Darkness there Mick

Good that the problem now appears resolved with the old sensor. I guess you'll be wanting to exchange the iffy new one for a replacement that works properly, if only to hold as a spare...

[bobins]

Lucas car parts are a..... proudly....... German........ owned........... company

Owned by ZF Friedrichshafen AG

That is actually why I picked the Lucas from the options I was offered, probably go for a Japanese one in my replacement negotiations!!

[mickthemaverick]

Good that the problem now appears resolved with the old sensor. I guess you'll be wanting to exchange the iffy new one for a replacement that works properly, if only to hold as a spare...

Indeed Jim, I have requested that from the supplier, Parts in Motion, who have supplied a lot of my service parts satisfactorily up till now.

[mickthemaverick]

Lucas car parts are a..... proudly....... German........ owned........... company

Owned by ZF Friedrichshafen AG

That is actually why I picked the Lucas from the options I was offered, probably go for a Japanese one in my replacement negotiations!!

[Gibbo2286]

Lucas car parts are a..... proudly....... German........ owned........... company

Owned by ZF Friedrichshafen AG

That is actually why I picked the Lucas from the options I was offered, probably go for a Japanese one in my replacement negotiations!!

Did nobody tell you Zeppelins go up and come down?

[mickthemaverick]

Following my tale of woe with punctures, described here, I decided to avoid similar 'unexpectedly unavailable' periods with my car by replacing the space saver with a 5th alloy to match the rest. A comprehensive search turned up a few options including 4 wheels with tyres for £96 but I decided to settle on this ad on gumtree:

https://www.gumtree.com/p/cars-vans-mot ... 1501219955

as I don't really want 3 extra wheels and so I don't need to fork out £96 when £30 will get me a wheel onto which Peter can put the offside undamaged tyre from my recent replacement of the rear pair, assuming he still has it of course

So tomorrow I am going down to Andover to collect it and then meeting my mate Bob for lunch on the way back and hence making the fuel cost more beneficial!!

[CitroJim]

That is a good plan Mick... My Picasso has a space-saver and I'm not keen on it. Problem is, the area where it sits is not big enough to hold a full-sized one...

Saw a sporty'ish Audi come flying past me warp-speed and then violently swerving back into lane wearing a space-saver Yet another Audi driver keeping the stereotype alive and well

[mickthemaverick]

I haven't tried it but I'm pretty sure the spare wheel well in mine is big enough to take a full sized wheel although it will possibly mean I'll have to give up the sculpted shelf that fitted on the space saver for tools etc.