thermostat help

[e30construction]

ok so im about to attempt to replace my thermostat on my m20b25 and I was just wondering if any body could point me in the right direction..all my coolant was just replaced when I did my tbelt which was about 500 miles ago so I don't plan to drain it all out..just w.e comes out when I go to remove the housing and tstat..I believe the housing is where the bleeder screw is so one correct me if im wrong..how much is gonna come pouring out when I start removing everything and what all do I need to remove?
thanks to any help given

[MR 325]

Yes the thermostat housing is the thing the bleeder screw is on top of.
It's VERY easy and only 3 10mm bolts. It's likely to spill a decent amount of coolant though. You'll have to refill and re-bleed.

You should really buy yourself an E30 Bentley repair manual if you don't have one.

[EatsHondas]

Yes the thermostat housing is the thing the bleeder screw is on top of.
It's VERY easy and only 3 10mm bolts. It's likely to spill a decent amount of coolant though. You'll have to refill and re-bleed.

You should really buy yourself an E30 Bentley repair manual if you don't have one.

+ 1,000,000 on the Bentley suggestion. If you look hard enough, you can get DL a free copy somewhere on the web. I forgot where I got mine, but it was definitely a link on a popular e30 forum. This book should be your BIBLE.

[ak-]

I just did this last night lol

Take off hose where it connects to the housing/3-bolts.
Take off 3 bolts.
Pull t stat.
Put on t stat the way it was pulled out.

Bleeding the system is more of an annoyance half the time than replacing the t stat.

[e30construction]

new tstat

just installed a new 75 thermostat due to it being super hot in the summer where im at and now when driving around my car is under the first line and at idle is between the first and half..just wondering if this is a bad thing or is it ok?

[Nick_S]

Did you bleed the system correctly?

[IAmGary]

Was it overheating before?

From what I've been told the standard 80C thermostat is fine unless you're dealing with tropical climates - Mississippi is hot, but not that hot.

If you install a 75 thermostat it will open at a cooler temperature preventing the engine from heating up as much or as quickly as it would otherwise. The car will use more fuel and may foul plugs and o2 sensor more quickly. You really want a motor to get hot for best performance.

The 80C thermostat should be find as long as the rest of your coolant system is working: unclogged radiator, sufficient coolant / water mixture, no collapsed hoses, working water pump, fan clutch that engages properly (should chew up a rolled up newspaper when the motor is hot and the fan is running), aux fan should work, etc.

[e30construction]

well when I did tbelt and waterpump we were having a hard time getting the air out but finally got it done..but it still wanted to get a little hot at times..like I was sitting in back to back traffic the other day and it got all the way to the third line before the tstat opened up and took it to the half and stayed there so I thought id put a new one in..i also figured having a lower temp one would help when it starts getting really hot out here...but from what u guys are saying I may not have made the best decision...one thing u guys make can make clear for me..when we wer pouring the coolant in we had a hose on loose so most of the coolant came out and we poured a lot more water in so would that have been an issue sry for the long post

[Thizzelle]

it's usually middle when idle and when driving it's to the spot yours is at idle. that is stock tstat spots

[e30construction]

yea that's where it was before I did the tbelt and waterpump..then for some reason it was getting a lot hotter but I thought it was either a bad tstat or way more water than coolant..so I guess the next thing I should ask is, should I buy another 80 thermostat or just go with the 75 tstat?

[ak-]

80c is fine and stock.
Unless you live in hot and humid climates as mentioned, or have a system that generates a lot of heat like a turbo charger maybe, 75c is not needed.
A 75c t stat will also make your mpg suffer a bit since the engine is now running cooler.

Water is 100% fine. Some people are against it because in the long run it can cause internal erosion or something. I believe spece30 racecar rules only allow water actually incase of an on-track spill so cars don't slip and lose control, so go figure.. racecars.

Maybe add some water wetter. Who knows if it actually does something (I never researched it), but consodering the chemical compound it's suppose to and physics don't lie right?

[IAmGary]

You really only need a little antifreeze for it to do it's job, if there's more than 50% distilled water it's still o.k. If you're having trouble bleeding the system you should drill a small hole at the TOP of the thermostat so air can pass through.

Found this, the white dot shows where to drill.

[e30construction]

ok cool thanks everyone..i guess ina week or so ill go ahead and buy another 80c tstat to get it running normal temp..and thanks for showing me where to drill the hole..for some reason my car doesn't like to bleed the air out

[jlevie]

ok cool thanks everyone..i guess ina week or so ill go ahead and buy another 80c tstat to get it running normal temp..and thanks for showing me where to drill the hole..for some reason my car doesn't like to bleed the air out

Your procedure may be the problem, try:

1) Using ramps or a jack get the front of the car 1' or more higher than
the rear. That will make the radiator and bleed screw the highest point
on the engine and facilitate removal of air.

2) With the bleed screw open, add coolant until no more air comes out of
the bleed.

3) Leave the filler cap off, or at least loose, and set the heat for max
temp and fan speed. Leaving the cap loose will prevent air that's still
in the system from causing a "coolant fountain" once the engine heats
up. Start the engine and allow it to warm up to operating temp. As it
warms up occasionally crack the bleed screw to release any air and top
up the coolant as necessary.

4) Once the engine is at temp bring it up to 2000-2500rpm for a few seconds
several times. Then crack the bleed until no more air is released. At
this point the heater should be throwing lots of hot air, which
indicates that the heater core is filled with coolant. You may have to
repeat this a few times to get all the air out.

5) Drive the car a bit, allow it to cool back down, and recheck the
bleed for air. Over the next few days you may get very small amounts (a
few bubbles) of air out of the bleed screw.

[Earendil]

ok so im about to attempt to replace my thermostat on my m20b25 and I was just wondering if any body could point me in the right direction..all my coolant was just replaced when I did my tbelt which was about 500 miles ago so I don't plan to drain it all out..just w.e comes out when I go to remove the housing and tstat..I believe the housing is where the bleeder screw is so one correct me if im wrong..

The Bentley, as others have noted, is a great resource for things like this.

how much is gonna come pouring out when I start removing everything and what all do I need to remove?
thanks to any help given

The Bentley won't help you with this one though :)
It's easier if you remove a few hoses, and I'd guess you're going to dump/drop/sling a quart or two of fluid down the side of your engine if you just dive in. If I were you I'd pull the drain plug on the radiator (drivers side on mine) and let a half gallon drain out. I think that'll be enough to keep it from going absolutely everywhere.

I run all water in mine with some water wetter, but I make sure it is distilled water, not tap water. The only reason I use water though is because my car spends a significant portion of its drive time on a track. For a treat car there is hardly a reason not to use coolant, as it won't freeze, will help protect, and maybe even cool a little better.