Hi all,MR2 MK1 owner with a problem

[moon]

Can anyone help? I have recently bought my first MR2 and am loving it, the problem is that it has a weird idle!!. It revs between 800 and 2000 on idling. Does anyone know the reason for this and a good fix for it? It also has a loud screech on start up, only for a few seconds (I know this is the fan belt, but don't know why it's doing it)

[adsaba1969]

welcome, when you say 800-2K does it fluctuate back and forth? Cause 800 is fine when car is warmed up, and 1.5-2K is normal while warming up

[MRQtwinturbo]

it sounds like you have a vacumn leak somewhere....

[jmill89]

If your idle jumps around after the car has warmed up it is almost always caused by air in the coolant system. A steady 2000 rpm when cold is normal, and it should gradually decrease to about 800 as the engine warms up. Air pockets in the coolant system will cause the temperature sensor to read incorrectly, thereby causing an idle that jumps around. It is very important in these cars that no air pockets are present in the coolant system becuase it could cause the engine to overheat.

I think this is the correct procedure to purge the coolant system(someone correct me if I'm wrong:

drain the coolant from the radiator drain plug, the drain plugs on the pipes under the car, and the one back on the engine block. Then close all these back up.

Open the air bleeder in the engine bay(follow the line from the overfill tank). Fill coolant until you see water in the clear tubing to the overfill tank. Close this valve.

Attach clear tubing to the bleeder on the top of the radiator driver side, and to the bleeder on the heater core. Suspend the hoses to the hood lid. Fill coolant until you see coolant in the suspended hoses is higher than the fill cap in the back. Close the two air bleeders.

Now put the fill cap back on but do not tighten. Run the engine for 3 minutes. top of coolant level, fill overfill tank to full, and tighten fill cap.

After all that you should have fresh coolant with no air in the system.
If you take it to a mechanic make sure they are aware of the special procedures for this car, and never let a quick lube place touch your coolant system.

As for your belt noise, it's just an improperly adjusted or worn out alternator/AC belt, there's no fan belt.

Jason

[SW21]

yup, it's a vacuum leak , same thing happened to my old accord...

[TRDMR2MKI87]

i had that same screetch in my MK1 a couple days ago. but it was worse it didnt go away every time i gave it some gas it would screetch all the way into third.

what worked for me was to loosen the alternater and try to get rid of some slack and tighten up the bolt.so far no noise for me but i dont know if it will work in your case wouldnt hurt to try.

[ToyotaTechGeek]

although all of the answers (except 1) sound like they would be the culprit, in an AW11, it is more likely to be a poorly bled cooling system. that coolant air pocket could be very bad if the car overheated. the TPS is another thing i would check after the coolant has been bled.

just a tip for coolant bleed procedure:
jack the rear of the car up as high as possible. i would open the heater (turn the heater valve to 'hot'. i also like to 'milk' the hoses.

[jmill89]

Oh yeah... Thanks for adding that, opening the air bleeder on the heater core wouldn't do alot of good if the heater wasn't open.

[moon]

It turns out it was air in the coolant. There is a hole in the radiator and that's what's causing it. So new radiator to be fitted this week and then fingers crossed no more problems.
Thanks guys

[feral4.mr2]

make sure the system is bled properly after the new radiator is put in, otherwise you'll have the same 'bouncy' idle problem.

i find having the car reversed up on ramps to be the best/easiest way of bleeding air from the coolant system. i only bleed the radiator, heater, and thermastat housing.