Just put the a12 with the A14 head in my 120Y.

Now it started and runs really good, but when you get on the throttle hard the temp starts to rise really quickly. As soon as you back off the throttle it cools down real quick too.

I was at the top of third just before and I looked down and the needle was just about to hit max on the scale.

Now did I stuff putting the head on?

Is this a timing thing? (too retarded or advanced?)

I'm just not sure.

Cheers, jon

Hello fellow DCD owner (yes, I too now own one!).

You may need to check the actual temperature sender, but before you do that;

Does the temperature rise in the same manner if you were to accelerate steadily?

Some senders have different specifications and may behave different in differing applications. I think racetech from South Africa had an issue similar to this where the readings were in fact false.

You can smell things when they get hot, the plastics start to stink a fair bit. I do not however, suggest you test it this way but perhaps you may recall?

Basically you need to establish if the reading is in fact true.

Cheers Chris, welcome to the club within the club

I did wonder about the temp sender. It doesn't read much of anything until the revs are up and then it just skyrockets. I didn't notice any funky plastic odours but the trans tunnel was nice n hot.

I'll look into this temp sender thing. Can u remember the title of racetech's thread on it?

Found the thread. Hmmmm looks like I'll have to do some playin around.

edit - are there diff temp senders for a12 / 14?

how do they work? - edit the second - ok so the resistor in the sender can wear out / stop working. Would that cause it to read nothing and then very quickly climb to max and then just a quickly drop again

Or would it just show that the engine was running hotter than it is all the time, even at idle?

My gauge doesn't even look like registering a temp at idle, even just after being at max.

Ahh Chris, I just realised there was a question in your post.

quote:
"Does the temperature rise in the same manner if you were to accelerate steadily?"

No I only does it when you're hard on the gas

Sounds like a compatability thing to me.

TO tell you the truth I have no idea but I reckon for the time being, until someone can really help you, check the contacts and maybe change the sensor.

Is there a chance you have an air pocket in the cooling system?

It could easily be the sender but also I didnt properly do the coolant. I just filled it and put the cap back on

I warmed it up but when I checked it a bit later I didn't notice a drop in coolant level. To check should I drain coolant and refill then do properly or just run it for a while with the cap off the rad?

You know how the dash works? It adds 12v at the dash and the sender provides a variable grounding resistor.

The more ground..the higher it gets. The more volts the higher it gets.

Check alternator is providing 13.8->14.4 volts when engine is running, rev engine and check that voltage is stable.

If your regulator is screwed, you might be pumping > 13.8 volts into your electrics, making things like fuel and temp to misread.

Otherwise I'd pull apart the 2 main connectors under the dash that feed the engine bay, and clean the terminals.

If you had a laser thermometer.. you could confirm if the engine is hot or not.

Most cars (and I haven't looked at wiring on a datto dash mind you) have ballast resistors on guages so that the higher the alternator voltage, they apply that to 'both sides' of the guage so that it always shows the difference between the sender and the alternator output - i.e. the 'real reading' . If the ballast resistor gets a break in it, the guage (on some dashboards there is only one for all guages, so it affects them all) will go 'up' a bit as engine rpms increase, and down at idle. If the alternator regulator is also faulty, and allows massive increases in voltage, the guages can swing massively.

When the temp runs up high, does it go straight back down to cool as soon as you back off the revs? If so, that's a sign of the above, if it stays hot when it goes back to idle, it's possibly a combination of other things.

Thanks for the help guys,

I'm def starting to think it is the gauge.

Today on the way to work I tried a few different things.

On my way to work I have traffic for the first 20mins or so then I get onto a hwy and its nice n clear. During the traffic bit I was really light on the throttle just in case it got hot and wouldn't cool down at the slower speed.

As the traffic cleared I tried giving it a bit less than half throttle and just let the revs build to max in 1st 2nd and 3rd.

No temp rise.

Then I tried reving 1st and 2nd to the floor and then backing off for third.

No temp rise.

Then, as I turned into my street at work ( I work in an industrial estsate I gave it full throttle through to the end of third.

Still no temp rise - It didn't even register on the gauge.

I dunno but it feels like the gauge is cactus.