Engine overheats, when air con turned on

[Pdavies99]

In general you should not need fans running all the time, if so then maybe wrong fitted (type) head gasket.

Have your coolant hoses collapsed internally, are they high grade type?

Are you running wirh plain water or recommended coolant, this can be important.

Many high performance cars actually have a 2nd radiator, worth considering?

Edited June 24, 2016 by Pdavies99

[kartman]

Sometimes i don't believe what I'm reading. He did write LPG right? That engine is famous for errors and oil consumption. It's a boxer and i hope you have been to a professional who advised you to put LPG on a boxer turbo engine.

SR20 is a boxer engine wow! do you understand what a boxer engine is?.

[giddyup]

In general you would surprised how often a sticking thermostat is the problem? Take out and try running with thermostat removed.

You should not need fans running all the time, if so then maybe wrong fitted (type) head gasket.

Have your coolant hoses collapsed internally, are they high grade type?

Are you running wirh plain water or recommended coolant, this can be important.

Many high performance cars actually have a 2nd radiator, worth considering?

The OP already said he's removed the thermostat.

[sead]

Tom.

As a owner of a Rx8 beautiful car you have a lot of Rx8 forums where you seriously should ask questions and not here. I would like to know a lot more of what generation lpg conversion kit and spark plugs you have. But i wish you luck in solving your problem. I myself would only convert a normal car 1.8l. I do think you got balls to play with conversion of a sports car where spare parts are expensive. Atleast in Sweden

[Somebodee]

By any chance are you running a 100% coolant mix? This is not good.

Contrary to popular belief this does not transfer/absorb as much heat as a coolant with a high water content.

In a country with high ambient temperatures I would run a coolant mix ratio of around 10-20% coolant the rest water (80-90%).

High coolant ratio lowers the freezing point substantially but does very little to increase the boiling temperature of the coolant. Infact it absorbs less heat as it is passed thru the engine.

Increasing the boiling temperature is mostly done by increasing the cooling system pressure.

[Don Mega]

Sometimes i don't believe what I'm reading. He did write LPG right? That engine is famous for errors and oil consumption. It's a boxer and i hope you have been to a professional who advised you to put LPG on a boxer turbo engine.

lol @ boxer engine.

DELETED

@ OP. flushing/back flushing a radiator is next to useless if it blocked, you need to pull the end tanks and "rod" the radiator.

Is the engine running a different tune for petrol and LPG ?. maybe it is a timing issue causing it to overheat.

Edited June 25, 2016 by seedy
flaming

[Sydebolle]

Had the same problem on different vehicles.

Initially the thermometer with two levels did not function properly and opened only for half-speed of the cooling ventilator which was not sufficient resulting in over-heating. Check/change the thermometer (usually a screwed in plug-kind of sensor taking the temperature from the coolant directly).

In addition I added a ventilator. Your radiator has one ventilator installed, usually positioned in the centre of the radiator.
Get that ventilator moved left or right and install a second ventilator in the empty space. If, for space reason, you cannot do this on the same side of the radiator (behind/in front) then try to use the other side - DONT FORGET to make sure that the air flow is from the cooler grill through the radiator and not the other way round. If you change from front to behind or vice versa the ventilator might have to run clockwise resp. vv.

The whole exercise will cost you a few thousand Baht; possibly the best investment in your vehicle.

All above of course only if the cooling system per se is functioning normally, no clocked tubing, compressor working etc.

[Don Mega]

^^^^ Ventilator = Fan ?

If the existing fan is engine driven how would one move it left or right ?

[seedy]

Nonsense post - and quoted replies - removed. Flaming post edited.

[whaleboneman]

Might be an electrical signal that is causing it

Yes, great advice. Check all your electrical signals.

[whaleboneman]

Had the same problem on different vehicles.

Initially the thermometer with two levels did not function properly and opened only for half-speed of the cooling ventilator which was not sufficient resulting in over-heating. Check/change the thermometer (usually a screwed in plug-kind of sensor taking the temperature from the coolant directly).

In addition I added a ventilator. Your radiator has one ventilator installed, usually positioned in the centre of the radiator.

Get that ventilator moved left or right and install a second ventilator in the empty space. If, for space reason, you cannot do this on the same side of the radiator (behind/in front) then try to use the other side - DONT FORGET to make sure that the air flow is from the cooler grill through the radiator and not the other way round. If you change from front to behind or vice versa the ventilator might have to run clockwise resp. vv.

The whole exercise will cost you a few thousand Baht; possibly the best investment in your vehicle.

All above of course only if the cooling system per se is functioning normally, no clocked tubing, compressor working etc.

so you know he has only one fan even though he states he has two?

[JAS21]

Reading some of these replies makes we wonder if ...... anyway enjoy your day

[JAS21]

Reading some of these replies makes we wonder if ...... anyway enjoy your day

Ace ... I was expecting someone ... like yourself ... to finish the sentence.

As it's wet and a Sunday ...a little entertainment

Some have really dug deep with their suggestions and they shouldn't be wasted...but thanks for the like anyway ...

[Daffy D]

Ignition timing!

Incorrect fuel mixture !

Well you seem to have tried everything else and incorrect ignition timing and weak fuel mixture can cause an engine to run hot.

[pgrahmm]

We still haven't heard whether physically overheating or just a 10-15% elevated gauge reading.....

[JAS21]

Hi All, thank you for the info, have back flushed the radiator, no debris flowed out, just some slightly dis- co-loured water flowed out.

The same symptoms still occur running petrol or LPG, as I said before the radiator is a large one.

Think the next step is to have the water pump checked again, and look into to a high capacity pump.

The engine bay does get hot, the radiator for the air con, sits in front of the radiator.

Regards Tom

Any outcome yet?

[tomtaylor1]

Hi All, thank you for all the information, suggestions.

Took The Car into a workshop that I have visited before on occasions always does a good professional job, rebuilds engines, tunes and sets up cars for racing at Bira and other circuits, have met various people from Myanmar at his workshop, who bring in there cars or engines to be set up for racing in there own country.

In his opinion, the water pump is ok, the radiator is well big enough as are the cooling fans, radiator cap i.i bar is fine, no blockages.

He suggested that the bonnet be raised at the hinges by 1", to let more air flow around the engine bay to be passed through more quickly.This has been done.

As yet have not had the time to fully check this out, as driving home it was evening raining and cooler, but I think has made some difference, will post again as soon as this has been checked out.

Regards Tom

[tomtaylor1]

Hi All, took the car for a good run, very little improvement in the engine temperature, the engine always returns to around 75/80 as soon as the air is turned off. Harder driving the temperature does creep up to around 90/92, but soon drops back, this is the same petrol or LPG.

As mentioned before the spark plugs are running a light gray colour and are for the LPG fuel.

Will try and get hold of a radiator cap 1.2 bar, now running 1.1.

Thank you for your patience and help.

Regards Tom

[pgrahmm]

That's only 197F - not necessarily overheating if pressurized with coolant can be good to 260-270F....

That's roughly a 13% increase experienced by putting approximately a 15% load on using AC......

Again - are there any physical signs of overheating like a chattering radiator cap or cooland pushed out of the overflow tank (with cold level correct), any bubbles bubbling up in the tank?

In a small system it's not unusual for the temp guage to rise & drop based on load.....My wife's Honda will do that but is always in the safe range.....

Edited July 11, 2016 by pgrahmm

[tomtaylor1]

Hi All, but with the air con on, the temperature would rise quickly up to 100 and higher, so at 94/95, then I turn it off, but it then soon falls back to temperatures in the 80's.

Thank you.

Regards Tom

[JAS21]

Cooling system is definately marginal for some reason.

They did fit the correct head gasket ... could it be the water flow restricted in part of the head and that water is catching the Tc.

What happens when you idle the enging with a/c on.

Actually l wouldn't have thought a little over 100C was bad news. It appears to run too cool when the a/c is not running due to no thermostat.

You could cut the bottom off a plastic bottle. Remove the radiator cap and seal it (the small end!) into where the cap goes ... I've used silicon before ... but don't drop any into into the radiator.

Add some water ...run the engine and see if you get a stream of small bubbles ... they will be entrained steam ...if you get massive bubbles ...um!

I'd still consider a 'proper' water pump though ....

Edited July 12, 2016 by JAS21

[Don Mega]

where is the fill point of the radiator in relation to the highest water jacket in the head?

[tomtaylor1]

Hi All, thank you for showing an interest in this problem.

Back to the shop, head gasket ok, the opinion is now, because the air con radiator sits in front of the main rad,and Rad for The Turbo partially blocks the flow of air to the rad also, an additional fan is required to push air through to the water cooling rad and engine bay, this would entail the area in the front to be modified, to allow the installation of a further fan.

A price for the work could not be given.

I am now thinking this matter over.

Regards Tom

[Don Mega]

does coolant temp rise when you are driving. say 100km/h on motorway ?

if yes than an additional fan aint gunna do squat.