E30 Zone

For anyone considering using waterless coolant, something happened today which causes me concern about it.

I bought the car with Evans in it. Personally, I wouldn't have bothered as I don't think there is anything wrong with normal coolant, however since it was in there, I wasn't going to bother changing it. I have had problems with temperature with this car with it not being very stable, rising in traffic or after hard driving. This suggests that the cooling system lacks the thermal capacity needed. However my car has a new water pump, larger e36 radiator, silicone hoses and electric fan so I doubted that was the issue.

Today I replaced the heater valve and had a nightmare bleeding the car, losing most the coolant in the process. As I need the car tomorrow I've filled it up with water (still with plenty of Evans left in). Now with the water mix in there, the temperatures are much better. Before it would creep up to just past half if left to idle for a long period/in traffic/after a bit of a pasting. I tried all that and it wouldn't budge from just after the quarter mark on the gauge now.

Looking at the specific heat capacity (the amount of heat that can be effectively absorbed) of Evans, it's clear why. Evans ranges from 0.64 to .68. A 50/50 water/ethylene glycol has a specific capacity of 0.82, making Evans 20% to 28% less efficient at absorbing heat!

Is that a problem? I'll leave that to you to decide. It could be argued that the fact it won't boil and should provide more protection at higher temperatures means it's a non issue, however I like to have a bit of headroom with my cooling system and it was getting too warm for my liking previously.

I've already posted about this (without the figures) on another thread tonight. Is this a weird coincidence or have you seen the other thread??

Weird coincidence! Hadn't even spotted it, I'll give yours a read

E36 rad on a e30 is a nightmare, if you got it on a M20 you should use a e36 thermostat for easier bleeding and for the rad to bleed off back into the expansion tank.

this stuff has alot higher boiling point that normal coolant ive looked in to this

but as it boils alot higher you engine gains about another 20-30 degrees in heat
i read some guy was running it and his engine was getting that hot he couldnt even touch it

Yep a lot higher, so there will be no localised boiling that can occur with normal coolant so in theory it will protect the engine better. I just wasn't happy with how hot it ran on the gauge. Cruising at 100+ in France (sorry, autobahns in Germany) it would creep up worryingly high

What was the pressure of the hoses like with the evans stuff?

What effect would a smaller water pump pulley have ?

DanThe wrote:What was the pressure of the hoses like with the evans stuff?

Dan,

That Edd China used some on that wheeler dealer program.
If you believe everything you see on t.v he ran the car up to temperature and removed the pressure cap, there was no pressure.

A correctly pressurised system should never boil anyway, if the pressure cap is at 2bar (abs) the boiling point should be 121 degrees for water alone.
Up that to 3 bar (abs) and your at 134 degrees.

Bar in absolute pressure, Thus 2 bar is atmospheric pressure +1 bar.
3bar absolute is the pressure cap break off on an e30, so atmospheric +2bar.

Not a fan of the waterless coolant, is should always be unnecessary.

I will note there is so much more to this but I'm no expert on it, we have to consider that the gylco mix changes the specific heat and boiling point, -50/50 mix = 107.2 Deg C boiling and 0.86 specific heat
There is also the flow requirements to consider, when these fluids are changed the required fluid flow changes as well due to the change in density of the fluid.
All a bit of a crap shoot without very careful calculation.

KW355 wrote:

DanThe wrote:What was the pressure of the hoses like with the evans stuff?

Dan,

That Edd China used some on that wheeler dealer program.
If you believe everything you see on t.v he ran the car up to temperature and removed the pressure cap, there was no pressure.

Yeah I remember that, I just wanted to hear it from someone I can trust

ross2009 wrote:this stuff has alot higher boiling point that normal coolant ive looked in to this

but as it boils alot higher you engine gains about another 20-30 degrees in heat

So, 100 guys have sat down for 100 days plus and come up with a head and block which will be stable at the correct running temperature and along comes a guy who says "lets run it at a big percentage higher! It will be OK lads !!"

Not so sure.

Mart.

martauto wrote:

ross2009 wrote:this stuff has alot higher boiling point that normal coolant ive looked in to this

but as it boils alot higher you engine gains about another 20-30 degrees in heat

So, 100 guys have sat down for 100 days plus and come up with a head and block which will be stable at the correct running temperature and along comes a guy who says "lets run it at a big percentage higher! It will be OK lads !!"

Not so sure.

Mart.

That and higher engine temps mean hotter combustion chambers, more heating of the charge before combustion, greater thermal expansion and stress, more loss of material strength and hotter oil temps.

Personally I would want to be heading down rather than up. Modern cars only run hotter for efficiency reasons (less heat loss from the combustion due to the lower ^T)

DanThe wrote:

KW355 wrote:

DanThe wrote:What was the pressure of the hoses like with the evans stuff?

Dan,

That Edd China used some on that wheeler dealer program.
If you believe everything you see on t.v he ran the car up to temperature and removed the pressure cap, there was no pressure.

Yeah I remember that, I just wanted to hear it from someone I can trust

You can undo the cap with the engine right up to temp with zero pressure release. It's a little disconcerting the first time you do it!

Thermodynamics is an interesting subject. I for one would not be running a waterless coolant, especially not on an engine which has its cooling flow in a longitudinal direction, basically this is all non ///M engines.

The ///M's have flow across the head/cylinders and have a better average temperature across the whole engine, they are fitted with external water jackets which forces the coolant to X flow across the head/block.

Why does this matter? Well water will not return to the same point until it has give off its heat energy, this is also true when under pressure (water expands when heated). So on a non ///M engine, water just heats up more and more as it travels down the cylinders.

Recently I fitted an electric water pump on the track car, data shows exceptional cooling delta and a much lower engine running temp (better for power).

ross_jsy wrote:
Looking at the specific heat capacity (the amount of heat that can be effectively absorbed) of Evans, it's clear why. Evans ranges from 0.64 to .68. A 50/50 water/ethylene glycol has a specific capacity of 0.82, making Evans 20% to 28% less efficient at absorbing heat!

Is that a problem? I'll leave that to you to decide. It could be argued that the fact it won't boil and should provide more protection at higher temperatures means it's a non issue, however I like to have a bit of headroom with my cooling system and it was getting too warm for my liking previously.

Would fitting a lower operating thermostat cure the problem ?

Well it would open sooner, however the issue is the system no longer had the thermal capacity to keep the temperatures at what I would be happy with so the temperatures would still rise.

Interesting that Andrew, didn't know M engines cross flowed the coolant.

Overall I see waterless coolant as a band aid fix. People who use it all seem to say that it's great because the coolant system isn't pressurised. So what? If your coolant system is correctly maintained this isn't an issue. I would say it's only beneficial if you have an incredibly old car.

Also of note is how viscous it is. Think how thick undiluted coolant is, it's the same. This increases how hard the water pump has to work, introducing yet more heat into the system and I would imagine it does not flow around the head as efficiently.

I am coming up to a week now with the water/coolant mix. Temps have been perfect in all driving conditions. I used to have to turn on my air con so the fan would start up in traffic to keep temps reasonable. Now I don't and the gauge sits perfectly still.

Most M20's with a blown head that I've seen have failed between cylinders 4-5 or 5-6 due to corrosion around the gasket. Combine that with the heat soak it endures at the rear once you shut the engine down and its a problem waiting to happen.

If you can do away with the corrosive water in the system and the increased pressure at shutdown then it sounds perfect for an old M20, Just blow £150 on Evans and fill and forget.

It would be a pain in the arse if something punctures the rad but I've never had that happen yet so I'm tempted to give it a go.
The only issue would be trying to get all the old coolant out of the heater matrix because I can't see how that prep fluid would be able to do the job properly.

Could your increased temperature be due to the fans viscose coupling not getting hot enough to lock up ?

Corrosion happens due to poor maintainence and not replacing coolant at regular intervals. Again, band aid fix using Evans.

I have an electric fan as I have an e36 rad but not sure how the engine running hotter would not allow the viscous to heat up?

It runs hotter due to simple physics. Evans can't remove as much heat from the system as a water/coolant mix. It's also quite a bit thicker, so won't flow as well.

To give you some idea, a spirited drive or traffic would see the temp move to past the half way mark. Now it stays rock solid just past the quarter mark. Even after a big rolling burnout followed by 10 minutes sat still at 3k (I wanted to test the cooling as best as possible) the water/coolant mix stayed between the quarter and half mark. I'm sure the same with Evans would have meant a cracked head.

If you want a band aid fix for a problem that doesn't really exist, go ahead. I would rather have a cooler running engine, peace of mind and maintain the cooling system properly.

ross_jsy wrote:Corrosion happens due to poor maintainence and not replacing coolant at regular intervals. Again, band aid fix using Evans.

I have an electric fan as I have an e36 rad but not sure how the engine running hotter would not allow the viscous to heat up?

It runs hotter due to simple physics. Evans can't remove as much heat from the system as a water/coolant mix. It's also quite a bit thicker, so won't flow as well.

Well that's the problem, I've not owned every engine I have from new so I have no idea how well they have been maintained in the past and how much corrosion has already set in. Taking the heads off to check for a problem that may not be there is a bit overkill and would be simpler to just bung the waterless gear in.

So if yours was running hotter with the Evans in it was the fan running for longer ?

Once up to temp, the fan never turned off unless I turned on the air con fan.

If all the slight positives of less corrosion outweighs all these negatives, be my guest and use waterless. However the feedback seems pretty unanimous that it's not great. Up to you

The hope is to use the stuff and keep the car looking original but it sounds like it would require parts like a specific temp stat (yet to be discovered) and a smaller water pump pulley to up the speed of the impeller to compensate for the viscosity.

The more I think about it, if the stuff is that stable you could do away with the thermostat altogether and just have a variable speed electric water pump run from a thermistor at the rear of the engine

A lower temp stat won't help, it will just take longer to get up to temperature. I would also be concerned about cavitation from speeding up a water pump impeller.

I don't see how it would take longer to reach temperature if the coolant runs that much hotter ?

The pulley can't be reduced that much as it has to fit over the input flange on the pump.
If you fitted that then you could possibly stick with original stat, changing too many variables in one go would just take longer to get to a stable result.

Will still take time for the coolant to heat up from cold though, and if it's flowing through the rad from the off, that's going to take longer.Hot running temperature is largely defined by the rate at which heat is lost in the rad. To run coolant with a lower specific heat capacity whilst maintaining running temp, you'd have to increase flow rate or fit a bigger/more efficient rad - or both. Thermostat won't do anything for running temperature, it just lets the engine reach the desired running temperature before opening to allow the rad to maintain that temperature.

^that.

I don't think you understand the function of a thermostat Martin

Motorhole wrote:Will still take time for the coolant to heat up from cold though, and if it's flowing through the rad from the off, that's going to take longer.

aye ? Bit of a contradiction. You sure ross ?

Motorhole wrote:Hot running temperature is largely defined by the rate at which heat is lost in the rad. To run coolant with a lower specific heat capacity whilst maintaining running temp, you'd have to increase flow rate

Hence the smaller pulley.

A thermostat won't effect the maximum temperature an engine will run at (providing it's not a ridiculously high temp stat), just how long it takes to warm up. You want an engine to get up temp as quick as possible, hence why cars have thermostats.

It should be noted my car has the lower temp air con stat already fitted.

Just been sat in solid traffic for half an hour with the temp gauge not budging from the first mark. I would have been nervous before, with the main fan running flat out and the air con fan on too and the temp would have been over the half way mark.

I'm a fan of if it isn't broken, don't fix it and I don't think there is anything wrong with traditional coolant. Also a fan of KISS (Keep It Simple, Stupid). So far you have suggested a lower temp stat, re-engineering the water pump and running an electric water pump as workarounds for problems created by using what I see as the wrong coolant.

I do think adding an electric pump to circulate coolant once the engine is shut down like on Vauxhall V6's is a good idea though.

I've read someone describe this as a problem to a solution.