High Revving N/A.....

[Nik_L]

Having a slight issue with my Rev 2 N/A.

When the car is cold, it idles at around 1800 rpm.

It takes about 5-10mins of idling before it drops to just shy of 1k rpm. In that time though it slowly drops.

Also during that time, it takes forever to warm up. When i go to work at 3am, i drive 2 miles and by the time im at work, theres still not much warm air blowing through the vents. Not as hot as it should be. When its up to temp though its hot.

Also, the temp gauge needle dosn't move much. When driving, and its up to temp, its barely sitting off the 1st marker on the dial, and when ticking over and up to temp, it sits just under halfway. But then start driving it slowly drops to near the bottom.

Any idea's??

[Slarty]

Sounds like the thermostat is stuck open/broken. That'll cause the high idle (ECU thinks that the engine is permanently cold) and the low reading on the temperature gauge.

[Nik_L]

Thanks bud i will have a look into that. Where abouts is it located and is it easy enough to change?? And if it is that, will a stat from a Rev 3 import fit on my Rev 2 uk car??

[Slarty]

Urgh, I "think" rev2's are in the same sort of area as rev3's but don't quote me on it! Standing on the drivers side of the engine, they're on the bulkhead side of the block, close by where your oil filter is located.

I think the housing is held on by 3 10mm nuts (2 on rev3+) but be careful, they nuts are rather soft and easy to round off.

Pretty sure the rev1/2 use a different size to the rev3+, TCB certainly list two different parts :

http://www.tcbparts.co.uk/ << then click on "Radiators/Cooling"

[Nik_L]

Great help bud, cheers.

Ach well ive got a Rev 3 that im breaking anyway so no harm in taking the stat out and seeing if they are the same.

Will report back with how i get on.

[TheBaker]

Mine revs high(1.8 ) at start up also(rev2), for about 5 mins then drops to normal, so is this not normal? I've never been sure if it was.

None of the other issues OP has though.

[xanthus400]

check the temp sender sensor too. My temp gauge didnt work and had issues with my co2 readings on the dreaded mot. same problem ecu thought the engine was cold so was over revving and fueling was shot. Changed the sensor and hav not had any issues since. Mine also revs at about 1.8 on start up and then drops to 1 in about 5 mins

[Canopus]

iI had a similar problem albeit hot air from the vents was okay but the engine just seemed to get cooler and cooler. I bought a thermostat but before I fitted it the temperature guage just stayed at zero. On further checking it turned ot to be the temperature sender and a five min fix. Easy to check the sender, just pull of the connector and earth it. The guage should read maximum. New sender unit from Halfords (about £9) and all fixed and now the car even warms up quicker!

[Nik_L]

Where is the temp sender located?? If it dosn't read maximum when earthed, does that mean its fooked??

[Slarty]

when ticking over and up to temp, it sits just under halfway. But then start driving it slowly drops to near the bottom.

Classic symptoms of overcooling. Because the 'stat is open all the time, you have coolant flowing through the radiator all the time. When idling it's not too much of an issue but as soon as you move off the coolant is cooled too much. What should happen then is that the 'stat should close up slightly to restrict the coolant flow but obviously in this instance it can't.

[Nik_L]

Right update time.

The thermostat has been taken out. Not sure why but i have an idea.

The previous owner took the car on a road rally thing, Rust to Rome, so im guessing he has removed it for the warmer climates in Europe. That seem like a reasonable explanation??

[Slarty]

Yep that's most likely the cause! What the previous owner should have done was fitted a lower temperature thermostat (TRD one), just removing it isn't ideal.

Pop a new one in and you should be right as rain

[Nik_L]

Infact having looked at it and the new thermostat, i think half of it is broken into the housing. Looks like the bit around the rubber gasket thing, is still in the housing. I think he's cut it and left the top half in.

And to top it off, i think the motorfactors have gave me the wrong thermostat.

Going by the pictures on ebay etc, ive been given a stat for a Rev 3.

Can't check it as the GF is away with the car.

[RikH77]

where is the temp sender/sensor located

my rev3 na doesnt show any heat when driving, when stopped/idling it begins to rise but set off again and it goes back to cold.

heaters working ok

any tips on this (project car but need this for MOT)

thanks

[abovetherim]

If it was me i would get one from Mr T or if camskill or TBC do OE ones then there. Reason being i have had a few T stats that don't quite fit properly from motor factors and with the mr2 being as they are i think the T stat is a critical component so well worth the extra £5 to go OE.

The temp sender is on the firewall side of the engine to the N/S and has a green plug. Next to it you will have the cold start timer with a grey plug. To test the temp sender you will need to remove it. Then with a multimeter you can measure the resistance at different temperatures
Basically at 0 deg you are looking at 4Kohms and at 120 deg it should be close to zero with a smooth curve of values between (would have posted the graph from the BGB but i can't seem to get it to work).

[Slarty]

The rule of thumb is that if you leave the car idling for 10-20 mins and the temperature gauge comes up to normal (just about half way) but soon drops down once you're moving, then the problem lies with the thermostat.

If you leave it idling at the temperature doesn't come up at all, it's the sensor.

As I said, that's rule of thumb, not absolute.

[Nik_L]

Sounds just like the problem i was having Rik.

Put in a new stat and all has been well since. Heats up nice and quick.

[RikH77]

any pics of where stat is located nik?

May just change both to be sure.

Not left it running since i got it apart from to circulate oil after change.

R

[Nik_L]

I don't have pics but its easy to locate.

Open the engine lid and look down from the drivers side. At the rear right hand side of the engine, where the oil dipstick is, you will see a large water hose. That hose goes into the thermostat housing. Remove the housing (iirc 2x 10mm nuts, 1 at the top which can be seen, and 1 diagonally underneath that you will need to feel for) and you will see the thermostat inside. Literally takes a few minutes to change, its p1$$ easy.

I would do the stat 1st before the temp sensor.

I have a working stat here from a Rev 3 that you could have if you want as its no use to me. Cover the P+P and i will pop it in an envelope and send it to you.

[RikH77]

decided to test this when i got in from work - left it running for 20 mins and it got to temp ok so must be thermostat.

Nik appreciate offer but got to make a Mr T visit soon so thermostat will be on the list.

Thanks for help guys

R