MogLite's cooling system

[bill van snorkle]

I am no cooling system expert but in my experience a rad/fan shroud, if you don't already have one, can make all the difference. A couple of summers ago, in preparation for a deisel conversion, I fitted a Toyota Landcruiser radiator to my 2 1/4 litre Landey engine, some 4 inches further forward than the original rad. Even with the 8 blade military fan the coolant temp was always in the red. After building a shroud to reach from the rad to the fan the engine runs so cool that the thermostat isn't enough and during our relatively mild winter weather I have to put a blind over the rad to get enough heat for the demisters to work.

Bill.

PS, I believe the boiling point of water is raised by 3 degrees F for every 1 psi at the cap.

10 psi cap =242 deg F boiling point, around 116 deg C.

[white90]

good thread Andy glad I read it as I just remembered there is no Antifreeze in the 90 after the last cambeltt swap..

[B reg 90]

Might be missing some thing here, but my views are:

Temp sender - if it's in the original postion (the outlet from the engine according to your original post) then you should be ensuring that you get the normal V8 engine temp at that point (~95??). Thats the temp the engine was designed to run at based on measurement at that point. If you move the sender to a cooler point in the system you will just be deluding your self about the actual temps within the engine.

Fan switch - any control system should measure the output of the system, otherwise the system does not have a feedback loop to the controler. The aim of the system is to ensure that cool water goes back to the engine - hence you should control the fans on this temp. Also if you want a 95C exit temp from the engine you will need to control the water temp back to the engine below this. Don't know the expected temp rise of water across a V8, but 15C seams a good guess. That indicates that the fans switch should switch on the first fan at say 80C and the second at 85C.

I personally think that a cooling system should be man enough to cope with any situation. With a standard landy set up you can take your motor and drive across deserts - the temp gauge will stay on normal unless there is something wrong. Other wise when the **** has hit the fan you will not react because 'it allways does that'.

Hence in my opinion on an electric two fan set up the second fan should only come on in extreme situations. I would suggest that your rad should be bigger with a bigger set of fans. Then it would run for most of the time on only one fan, the second only kicking in when it's realy hot, the rads covered in mud etc.

Adrian

[mattD110td5x]

yes a great thread... sitting comfortably from my armchair I think I would guess.....

- the temperature gauge you are using is probably reading around 5C over,

- the lower mass of water in the system means it is a little underdamped and maybe is giving a bit

more hysteresis probably another 5 or 10C,

I'd try putting your temp gauge sensor into gently boiling (simmering) water at sea level and check it reads 100C.

I wouldn't worry about the Xeng sensors they are probably spot on.

If you are going to be plodding in winch challenges then I'd look at a bigger rad or bigger hoses,

only to raise the mass of water not to increase the cooling efficiency,

ttfn

Matthew

[reads90]

TWo things Andy

How about putting in a lower temp thermostate, cost little so worth a try

Also here we don't have antifreeze but coolant instead. Don't quite know the differance as we still have anti freze in the 90 (from the UK) worked fine in the outback at 45 degrees C don't quite know how much use it wa out there

[simonr]

OK, my 5p worth.....

First try removing the stat - see how much of a difference it makes.

If it makes a big difference, then the stat is probably broken or at least sticking.

If it makes little difference then I would look at the cooling effect of the radiator. Either the flow is restricted or the fins joining the cores have disintegrated (they often look perfect from the outside, but have lost contact with the cores in the middle).

It is probably not a coincidence that all (I cannot think of an exception) cars with electric fans, measure the temperature of the outlet, not the inlet to the rad. Sometimes the sensor is half way up the rad, but always on the outlet tank.

I agree that putting the fan on the inlet will make the system run cooler overall - but the fan will be running continuously when the engine gets up to temperature. This results in much shorter fan life and a loss of some of the energy / fuel saving the eleccy fan can give you.

Why do people fit them in the top hose then?

Because it's easy to get to! Imagine trying to fit one of those little Kenlow capilary bulb things in the bottom hose - you would never get it to seal!

Si

[02GF74]

see what BBC said earlier - basically is there really a problem with the temps? (personally I would not liketo be running over 95)

just een downstairs to look at various v8 manuals - they say thermostat starts to open at around 80 - so I'd would say fully open about 85 - the housing is at the top of the engine so this is reguoloating the max. water temp to around 85 (I said that ^^^ but did I say 85?).

again whether you put fan swtich sensor in top hose of bottom shouldn't make that mcuh difference - but you;d want the one in the lower to sitch on at a lower temp than one in top since the top one mean that water willleave the rad at a lower temp than if thesame siwtch is in the bottom hose.

there is hysterisis all ove the place- fan switches and thermostat so without having more precise data re: air flow, water flow, , heat transfer from the rad ... a lot of what I'm (and probably others) are saying is a bit hit and miss but you can get the result you want with a bit of thought and trial and error.

deffo put some anti-freeze in; I'm using the water wetter, relatively cheap - cna;t say it is any better since I did not do any like for like tests but is hasn;t made it worse. Also use de-ionised water from wilkinsons.

fans to be as close to rad as possible, with cowls to maximise efficiency.

TBH, the first thing I'd do is to try lower temp switches (in lower hose unless you fit in top), get 2 at 5 and 10 degree less that what you have and swap them in (my guess somemting like 80/85 or 85/90) would make me happy.

do you know temp of your thermostat?

[Bull Bar Cowboy]

The thermostat on all EFI’s is 88c………….. so the engine temp normally sits at 88-90c

Fitting a cooler stat will not solve a problem ………… to solve an over heating problem you have to get rid of the heat.

However, I don’t believe there is a problem…………. although it seems as though Moglites cooling system may be marginal.

Ian

[Lara]

Andy,

By the time you have read all these answers you could have gone and done two days work to pay for the new bigger rad that you realy need, Bills idea of making a shroud is a good one and yes it realy does work as he says, but saying that, you are banging your head against a wall with the rad in an off road vehicle if you are marginal on cooling efficiency, as you obviously are. Just bite the bullet and get a nice thick ally cored unit as big as you can sensibly fit, make a shroud and be happy in the knowledge that even when half of it is covered with mud you are still going to be able to cool the engine. Job done Once!

Lara.

[FridgeFreezer]

There's also the issue that any air that radiator gets has been drawn a cross a hot 3.9 V8 and tubular exhaust system rather than the traditional direction of cold air hits rad and then blows across engine. Hot "cooling" air can't be helping.

[Outrage]

Well it isn't much of a system TBH

As a reminder

• Transit radiator - rear mounted
  
• 2 x Cosworth fans - sucking
  
• X-eng 2-setting switch in the bottom rad hose
  
• tee from bottom rad hose to standard expansion tank
  
• No heater or associated hoses
  
• VDO sender in stock position on V8 intake manifold
  
• VDO gauge matched to sender
  

Yes I know the rad could be considered a little on the small side

Yes I know adding more water to the system by plumbing in a heater/2nd rad would help

But before I re-design I'd like to make sense of what I've got.

Whilst shaking down at Seven Sisters I was seeing a running temp of approx 100C - which in September is a little hot for my liking.

When it went to 105 - the second fan would kick in from the x-eng switch

I though 105 was too warm for the 2nd fan to be kicking in, and I'd like it to run much cooler than that.

Fridge asked a pertinent question

> Where is your fan switch fitted relative to your temp gauge sender?

> Remember those switches have a 5-15deg hysteresis between off and

> on so

> it's not going to switch at exactly the same temp.

> J

_

Hysteresis - good word :-)

The temperature sender is in the stock position in the V8 intake

manifold - its VDO to match the gauge.

The fan switch is an X-eng jobbie in the bottom radiator hose.

I'm assuming that the water flow is pumped "out of the top of the

water pump"

into the top of the rad

Out of the bottom of the rad

Past the x-eng fan switch

Back into the block

Assuming the gauge and fan switch are accurate.

The 2nd fan comes on at about 105C

Yet the X-eng switch switches the fan on at 92C (13 degree

difference across the rad with one fan on)

I'm thinking it doesn't matter what temp the water comes out of the

block (within reason) it's the temp that it goes back into the

block - ie to show the rad is doing its job ?

So I could re-position the temp gauge sender to the bottom of the

rad pipe ?

Or I could stop panicing about 105-110C on the temperature gauge

because I know its in the wrong place and it is therefore reading at

least 13degrees high (possibly more with the 2nd fan kicked in)

True ?

Hello, not sure I understand how your setup is arranged but i'm assuming that the rad is on the back and therefore is not subject to the normal natural cooling as it would be at the front. I see you have a 2 setting switch which I assume means that at one temp setting fan 1 kicks in and at a higher temp fan 2 kicks in.

Assuming the above is true...

As you already have a reduction of airflow would it not be prudent to have one fan running continuously to make up for the lack of natural airflow and the second fan kicks in at the same temperature that a single fan would on a radiator that's traditionally mounted?

Obviously this means a fan will be running all the time but better to keep the temperature constant from turning the engine on rather than turning the engine on and waiting till its got pretty hot before starting any forced air cooling. This will undoubtedly mean you go through replacement fans faster but it's a trade off in fans versus the superior location of the radiator.

I could just be talking bo**ocks based on my assumptions!

Cheers,

Lee

[Lara]

Hi Andy,

Just gone through your build up pics and looked at your cooling system, The rad does seem to be large enough so I take back my last answer.

Some relevant and quite important questions that I would ask are as follows though.

Where is the air to cool the rad comming from?

Is the air flow masked by any large objects?

Where does the hot air go after it goes through the rad?

Is there anything in the way of the exit flow?

Do I have an absolutely enormous cooling fan to counter these arguments?

Is said fan ducted to give maximum efficiency?

Lara.

Lovely looking truck by the way!

[MogLite]

Lara - blimey - you aren't wrong there are a lot of opinions - which is good - I think

I'm not sure the rad you saw in the build-up pictures is the one I am running - that one is for a big-block Ford and wont fit anywhere.

I'm not about to drop several hundred pounds on a custom rad without fully exploring the fact that a brand new £45 Transit radiator cannot be made to work first.

Here are some more pertinant pictures I've dug out

I don't think the mesh between the rear lights is letting enough air out. I'm gonna up the hole size from approx 3mm to about 20mm.

The engine bay sides are only partially enclosed so the air the fans will be drawing in will be warm.

I don't think I can do any ducting that will help, in fact it may well hinder.

A cooler switch, or wiring both fans off of the cool side of the switch may help, anti-freeze will go in when I've finished messing about, and probably Water Wetting before the summer.

Today I've picked up a Yamaha FZR 400 radiator and fan. The rad is about 18" by 8" and will go under the dash. The rad itself only holds about 0.5l, but by the time I've run about 8m of 18mmID piping to it, I'll have about an extra 8 litres of water in the system - which can't hurt. Warmish footwell will be a bonus too - I'll turn the fan over in summer so that it extracts !!

Andy

[Mark90]

My 2p's worth.

Temp guage - keep that in the hot bit, you wanna know how hot it's getting not how cold the coolant is when exiting the rad.

Fan switches, top hose or botton hose - I don't see that it makes much difference. You want to provide sufficient cooling such that the high engine temp (that you are reading on your guage) doesn't go above specified limits. If the coolant is too hot coming out of the enegine you need more cooling so switch fans on, or if the coolant is to hot coming out of the rad to provide sufficient cooling you swict the fans on to provide more cooling. The only difference is the temp at which the fans would be switched to maintain teh same engine temp. So you just pick the right intermotor part to give the appropriate maintained temp for the engine.

I ran a standard V8 rad (with heater etc) and twin mondeo fans. Off road doing slow work with no forced air cooling one fan runs most of the time, in fact it's on and off but probably on 60-70% of the time. Even when working the engine hard it doesn't get hot enough to bring on the second fan, the low temp fan just spends more time on - which is quite suprising as my fans are possibly switched at too low a temp as I'm using a switch supplied for bottom hose fitting (from Si) in the top hose. I may change it for a hotter switch but then again I don't think having the fans on a tad early is a bad thing.

If I switch both fans on the temp drops big time, I can watch the guage drop. This extra cooling capacity and the need for only one fan in even hard use means if the rad gets seriously blocked etc I should still be ok with the two fans, or as happened at 7S the other w/e one fan started to blow fuses after being dunked in the pond, no big drama the other fan coped, I just swapped the temp switching wires over so the good fan became the low temp one.

I think you need to look at cooling capacity as it does seem marginal. So rads, fans and air flow, you need more of each IMHO.

Just had a thought re oil cooler - you have one fitted if i'm correct? Hows the oil temp? Could you get rid of more heat that way?

[Andy]

having seen the build pics, im joining in the comments saying the cooling air is probably too hot. i'd try & get some sort of ducting in so at least part of the air flow through the rad is cool air from outside the engine bay.

[geoffbeaumont]

Andy,

How hot do those silencers get? It looks like they're right next to the rad with no heat shielding, which can't be helping?

What's the direction of air flow? If air is flowing over the engine first, would it help to rig it the other way round (given Moglite will almost never be going fast enough to cause flow problems with this arrangement)? That way you should get much cooler air over the rad.

Could you add a second pair of fans on the other side of the rad, and rig them so one pair come on at the lower temperature and the other at the higher one (possible paired as opposing fans rather than both on the same side, as the stationary fans would otherwise hinder air flow a bit).

[Hybrid_From_Hell]

Andy,

Have read your post and skimmed through the others so excuse if already said.

I had loads of overheating (or running F hot at least) problems with the old hybrid, so here is what I learnt.

1 - Ensure the gauge and sender is reading correctly

2 - Make sure that there is no air in the system and fully bleed

3 - with a V8 run 50% more antifreeze to water, more Anti freeze helps lower the heat

4 - If you can't cool the rad any more then cool the oil with a big oil cooler and fan

5 - rads

a- the bigger the rad does not equate with the cooler it runs, capacity is one thing but flow of air is another both it terms of what you can get through the rad and also fan wise.

b- engine fans inc viscous can pull air in hugely, and then on the other side of the rad go for pusher, good sources are Scorpio Granadas which are about 16" and scrappy cheap

c- Sender tripping in a fan the setting in crucial, cooling system can reach a heat that when they get there its all too late and getting in down again is next to impossible, get the heat out quicker - IE reset the fans to come on earlier

d - air flow - rads are not rads, I run a 7 core caterpillar core BIG tubes (= more water) and BIG gaps = air easily flows through, 7 core = depth, so I have a 2.5 TD rad (tanks are big) but as std the core is 1 inch narrower than the tank depth, mine is "level", = more water

e - header tank is essential, make sure it works and is higher than the highest point in the system

f - flow of air - make the shroud FORCE the air through the rad and NOWHERE else, block off all the other options

As you will be a Very slow MPH but poss High RPM you have no flow, so the other route is to get the heat AWAY from the engine, get a smoke stick and light up with all the fans on, seeing where the air flow goes when sitting still can be amazing.

Smaller pulley on the water pump will s[peed up flow rates, but if the system can't get the heat out its a waste

As a last easy option there is some stuff you can buy which is a heat dispersant added to the water, expensive but I know others who use it and it helps.

Just shoving a bigger rad on without incorporating the above comments will have some effect but nowhere near as much as a sorted out flow and control cooling system

HTH

Nige

[geoffbeaumont]

Could you add a second pair of fans on the other side of the rad, and rig them so one pair come on at the lower temperature and the other at the higher one (possible paired as opposing fans rather than both on the same side, as the stationary fans would otherwise hinder air flow a bit).

Scratch that - I just looked properly at the photo's, and I think I described what you already have!

[FridgeFreezer]

Further thoughts:

- Extractor or even blower fan mounted on the engine cover to get rid of heat around the engine rather than dissipating it through the rad fans

- One stage on from smaller water pump pulley - Electric water pump = max flow at any engine RPM then the rad is always working at peak efficiency, otherwise you have water going too slowly though the rad which means it has more time to heat up again in the engine as you're at low RPM a lot.

[MogLite]

4 - If you can't cool the rad any more then cool the oil with a big oil cooler and fan

Yeah got that - got a approx 10" x 10" oil cooler with a big fan on it.

Got huge transmission cooler too, so shouldn't get any/much heatsoak through that.

e - header tank is essential, make sure it works and is higher than the highest point in the system

Yep header tank is nice'n'high. Its tee'd into the bottom hose. If you don't screw the cap on properly steam esacapes - if you do - it holds water. Is there anything more to them than that ?

f - flow of air - make the shroud FORCE the air through the rad and NOWHERE else, block off all the other options

Yeah done that too. shroud and closed cell foam. Fans are very close to the rad.

As you will be a Very slow MPH but poss High RPM you have no flow, so the other route is to get the heat AWAY from the engine, get a smoke stick and light up with all the fans on, seeing where the air flow goes when sitting still can be amazing.

Damn - and there is the winner. See where the airflow is going - off to the plumbers merchant/fireworks shop for some smoke tablets

Just shoving a bigger rad on without incorporating the above comments will have some effect but nowhere near as much as a sorted out flow and control cooling system

Absolutely

[dollythelw]

.......or fit a nice sensible diesel...

[Hybrid_From_Hell]

Erm

Jez, since when have you been "sensible" ?

Nige

[dollythelw]

Ive seen pictures Nige..........

just another random rambling.. I wonder how much airflow disruption is caused by the mesh panel the lights sit on - Andy is there a "firewall" the other side (engine side) of the Rad as well?

[02GF74]

Ive seen pictures Nige..........

just another random rambling.. I wonder how much airflow disruption is caused by the mesh panel the lights sit on - Andy is there a "firewall" the other side (engine side) of the Rad as well?

yeap - just saw that picture; my rough estimates is that 1/3rd of the radiator is obscured by the lights; then the mesh is too fine. I would put a stronger but wider spaced mesh or maybe even bars - you won't have the same problem of pigeons/debris being thrown into the radiator like you would if it was on the front but more likley reverse into something chunky hence - the bars - you can space then to be further out from the rear.

For sure those lamps should be moved out of the way.

All these little tweaks will pay dividends.