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Removing the Thermostat. Adverse results?
scoop - 17/8/11 at 06:54 PM

My poor little polo rad is struggling to keep my 2l pinto cool these days it seems. Went out for a 6 mile round trip round town today in terrible static traffic and the temp. gauge was hardly out of the red and the fan flat out. So, when i got home i remomoved the thermostat to keep the fluids flowing.
Now im thinking, what are the adverse effects from such a move? I wont be using it again for a couple of days so if you are going to tell me something terrible will happen i can always put it back


mookaloid - 17/8/11 at 07:06 PM

It should be adequate if everything is in good condition and there is enough airflow.

If you do take the stat out then you should put a restrictor plate in ( stat with middle removed) but it is better to have working stat - try a cooler one? 82 deg?

Flush the system out check the fins are ok on the rad - not corroded

make sure the air flow gets through the rad (not round it) maybe use ducting to the rad from the nose cone?

is your fan running the right way?


ritchunt - 17/8/11 at 07:10 PM

I did this mate with my c20xe, not because it overheated just didnt really see the point in it been there as i had no heaters? Anyway i was using a polo rad and it kept the car cool no bother didnt have to use a fan tbh it was just just used on trackdays, this is just what i found other people may disagree


scoop - 17/8/11 at 07:19 PM

Rad was new last year. Fan is running the right way and before fitting the rad i flushed and reverse flushed the system and it has 33% coolant. I have vented front panels and holes in the bonnet and its still boiling over! Stat had to go didnt it?


Greenie - 17/8/11 at 07:21 PM

I took mine out due to the same issues, fan never off and temp gauge in the red, fan now come in when it shpiuld and temp gauge runs at steady 80...... Cars performs well?.

Worth a try.................


blakep82 - 17/8/11 at 07:27 PM

a thermostat in the system will get it up to temperature quicker, and stop the engine running to cool

but this isn't the problem,
removing a thermostat won't make you engine run cooler! unless its faulty and isn't opening when the engine's hot...
if its working properly, it should open properly and allow coolant to flow.

as said, check the fan is blowing properly through the radiator, make sure air can't get round the radiator isntead of through it. you might even have something not plumbed together right.

but imo, removing the thermostat will NOT fix your overheating problem


loggyboy - 17/8/11 at 07:27 PM

Only real adverse effect would be the engine would take longer to heat up therefore oil would take longer to get up to its optimum temperatuer.


scoop - 17/8/11 at 07:34 PM

Its plummed as per an old thread of mine which Flak Monkey answered with a great diagram and have seen others with the same since. Maybe the 'stat wasnt working properly then but im going to give it a go without from the responses so far.


britishtrident - 17/8/11 at 07:36 PM

Running without a thermostat is seriously not a a good idea the bottom half of engine will run much to cold.

First thing to do is check the ignition timing is not too retarded. Retarded ignition causes and excessive amount of combustion heat to be rejected to the cooling system and exhaust rather than doing useful work driving the pistons.

The next thing to check is that you have a by-pass hose fitted without a by-pass connection the engine will almost reach boiling point before the thermostat can open.


scoop - 17/8/11 at 07:53 PM

The engine timing is something im having done on friday. Im having a cam timing wheel fitted and the ignition timing set after that. Im not expecting it to be retarded though as i normally have it set at 12 degrees @700rpm as per the tuning book.
I do have a bypass pipe fitted between the 'stat housing and the expansion tank.


cliftyhanger - 17/8/11 at 08:10 PM

As above, the system doesn't work with a (properly functioning) thermostat there is a problem elsewhere. Running an engine too cold is not at all good, and if the system is correct, the car should run very cool when used. Plus if it is actually at normal temperature, you have little leeway when you hit traffic or whatever.
Could just be the rad is not big enough? I know many people use the polo rad, but I suspect the effectiveness varies car to car.

Well worth investigating carefully, and find a better solution.


RichardK - 17/8/11 at 09:13 PM

Can you see coolant being circled in the system as it warms up? I have a pipe that goes to the top of my expansion tank that acts as a breather and it got blocked somehow with what looked like a small ball of ali rad fin sheet, must have been in the inside of the rad and this prevented the system from breathing and caused a similar problem, removed it and could then see the coolant flowing back into my tank as it should.

Been good as gold since..

P.S I wouldn't take the stat out either, it's a bodge not a fix imho.

Cheers

Rich


scoop - 17/8/11 at 10:27 PM

Rich, i know what you mean and i did have. I must admit that i didnt check that before i made the move. Will report back tomorrow after ive fired it up and let it run a bit tomorrow.


coyoteboy - 18/8/11 at 03:45 AM

As above, stats dont make your engine run hot, but removing them will make it run cooler for longer and possibly cooler in normal use - not good.

Your rad/fan combo need sorting if your pump is working, leave the stat in.


snapper - 18/8/11 at 04:47 AM

If you remove the thermostat completely you can seriously bugger up the water flow, some super rods and oval racers cut the guts out of the thermostat and leave the plate with a hole in it.
Personally I would recomend trying the 82 degree stat from Burton performance it made an absolutely massive difference to my cooling issues.
I also drill a small hole in the stat to bleed water through and allow air out


craig1410 - 18/8/11 at 07:47 AM

You should at least use a restrictor ring which you can make from an old 'stat. The restriction increases the water pressure slightly in the cylinder head which prevents bubbles forming and thus hot spots. Any air will then escape through rad bleed pipe.

I say fix the problem, don't bodge it.


hellbent345 - 18/8/11 at 09:41 AM

when you say you have vents etc, do you have ducting to the radiator as well? Honestly, if there is any way at all that air can go around the radiator rather than through it, it will go that way cos its easier, could possibly be as simple as that. Try duct tape and cardboard to really seal off any place the air could go around the rad, and see if that makes any difference (its what we did on the riley 1.5)


scoop - 18/8/11 at 09:15 PM

Have just ordered the 82 degree from Burtons Ebay shop.
Im running the car about 30 miles round trip tomorrow for the MOT with nothing in place of the 'stat and will let you know how i get on.


scoop - 19/8/11 at 04:51 PM

Much better with out! Nice almost non stop run to the test centre though. It only got above half way on my estate when nearly home. Might have waisted my money on the new 'stat.


scoop - 19/8/11 at 04:52 PM

To answer a couple of other questions; the overflow is working and the rad was positioned as far forward in the nose cone to mex the airflow. I dont see the need to box it in.


coyoteboy - 19/8/11 at 05:08 PM

Pressure difference you'll get across a restrictor plate (which has enough flow to allow proper cooling) will be negligible and so not worth doing IMO. I just never saw the point in removing a stat or running a cooler stat - it does nothing but show a misunderstanding of how the cooling system works?

As for boxing your rad in, you'll get a vastly increased airflow through a ducted rad in comparison with one in open flow, but you have to seal it in properly and not leave gaps around the edges etc.


Strontium Dog - 19/8/11 at 06:06 PM

quote:
Originally posted by coyoteboy
Pressure difference you'll get across a restrictor plate (which has enough flow to allow proper cooling) will be negligible and so not worth doing IMO. I just never saw the point in removing a stat or running a cooler stat - it does nothing but show a misunderstanding of how the cooling system works?

As for boxing your rad in, you'll get a vastly increased airflow through a ducted rad in comparison with one in open flow, but you have to seal it in properly and not leave gaps around the edges etc.


All true!

Running without a stat is a great way to fubar your engine in double quick time! If you can't control the temperature then find out why instead of bodgeing it and using radiator ducting would be a good start!