Weird temperature read outs!

[boomshanks]

Hi,

I took my 111R for a spin last night. As usual, I waited for the temp to get up before giving it a blast. Funny thing happened - when I was driving it "enthusiatically", the temperature was dropping dramatically, then returning to normal when I eased off. When I say dramatically, my car, when warmed up, sits at 88 or 89 degrees, but I was seeing it drop 10 degrees in about 10 seconds under hard acceleration, then return to normal in about 10 seconds of easing off. Clearly, the engines temperature wasn't fluctuating that much - in fact, I would expect the temp to be about constant, so I put it down to a dicky sensor. When I got home, I started to think about it some more and began to worry that it might be more serious - why only drop under hard acceleration?

Has anyone else had a similar experience? Is it anything to worry about?

Thanks

B

[Mr_C]

because the water pump is pumping the water round faster so it gets from the rad to the sensor quicker.

[boomshanks]

My car is in for a service today, as it happens, and I mentioned the problem to the mechanic a few moments ago on the phone. He said that this is a known problem on the earlier 'yota engine, for which there is a known mod. Ring any bells?

Thanks

B

[griffter]

In that case my 111S must have had an engine swap, as I've noticed this!

I put it down to greater coolant flow due to pump turning more quickly and far higher airflow through rad under speed. The coolant capacity of the K series is so low that the coolant must cool very quickly under the right conditions.

[NathanE]

When the 2nd cam comes on the thermostat opens and the water pumps much faster than normal.

It's just a trait of the 111r's. They all do it.

Don't worry i'm sure your head gasket is fine

[LivinLaVidaLotus]

boomshanks said:

My car is in for a service today, as it happens, and I mentioned the problem to the mechanic a few moments ago on the phone. He said that this is a known problem on the earlier 'yota engine, for which there is a known mod. Ring any bells?

Thanks

B

Yes, known isuse, came to light again when the SC had the same issue - and it caused the limiter to kick in on someone when they were on 2nd cam. Don't think it's quite as bad as that on the 111R. It is as others have said down to the coolant loop opening up fully when on 2nd cam. I always make sure I have a few minutes longer before giving it full beans, kick it up to 4.5-5k rpm which causes the loop to open. Let it get warmed fully before giving it full 2nd cam treatment.

[gdr]

My 08 Exige S pp did this, I believe there was a faulty batch of thermostats that would bypass too easily when system pressured up at higher revs. Changed on warranty and steady water temp ever since.
May seem harmless, but recommend you get it seen to - if temp drops below 70C the ECU will cut revs to below the cold limit (6000 rpm or whatever) which could result in unpleasant surprise.