Pug 306 over-heating (or not)

Jul 26, 2006 3 Replies
T

Hi,



I have an 'S' Reg Pug 306 Meridian 1.4 - recently the engine temperature gauge has started creeping up above 90 especially when the engine is under load it creeps up into the red. The fans work OK and I can't see any leaks etc.



Got home last night, left the engine running on the drive, temperature dropped back down to normal 90 , noticed that whenever I put a piece of electrical kit on, the temperature gauge climbed instantly - switch it off then it dropped back again. With temperature at 90, I put the cold blower, rear heater, hazard flashers and main beam on and sure enough - up jumps the temperature needle into the red. Switch everything off....back to 90 again.



Any ideas ? Thinking its an Electrical problem, the Haynes manual wiring diaggram shows an Engine Coolant sensor and an Enginer Coolant sender - any ideas what the difference between the 2 is - I was going to replace one (or both).



Cheers, Tim


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S

Tim,

I've heard of this before. I'd suggest checking for an earthing problem in the first instance. Look for corrosion of the wiring from the battery negative to the car chassis. Replace it if necessary. This MUST be a really good solid connection or you are asking for problems. Similarly, I seem to recall that there is another wire that earths the engine itself to the car chassis. If you have a poor earth connection like this, then when you turn on something that consumes current from the battery, a small voltage appears at the sensor wiring which can cause incorrect readings.

Hope this helps,

- Steve

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D

Negative earthing strap goes from battery to engine, and then from engine to chassis. Standard wiring was to have both leads crimped into a single connector on the engine. I had bonkers electrics problems one time (generally not starting, sometimes starting and saying I was doing

140mph and then back to 0 in half a second whilst all number of relays were clattering!). All traced to a broken earth strap. Lead from battery to engine was fine (hence starter turned etc) - but strap from engine to chassis was intermittent. When it made connection, ECU was connected and it would start, any movement then made an intemittant connection, causing dodgy readings etc. AA guy fixed it for < £5 (for a new earth strap) and everything has been fine since. D
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T

Steve,

Bingo ! The earth strap had completely corroded from the engine to the chassis - spot on with your diagnosis - much appreciated.

Will fit a new one tomorrow and fingers crossed it will fix the problem.

Cheers,Tim.

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