Horizontally mounted radiator?

[Mehrts]

Has anyone tried running a radiator that is mounted horizontally (flat)?

I've been thinking about doing a rear mount setup for a while now due to having the standard front mount continuously block up with mud and being hit by branches , but I don't have much room on top of the flat deck. I also use the deck for carrying things as it is. I was thinking about starting from scratch with a tube deck, but to be honest, it's not really needed as what I've got now suits me just fine.

I do however have a ridiculously large amount of free space under the deck and this got me thinking about the possibilities of mounting the radiator flat(ish) underneath the deck.

Some yanks have given it a go over in the States, but I can't find any info on any issues that they ran into. Most people are only focused on the air & water flow through the radiator itself, which isn't a problem.

I was thinking that vibration/knocks would be a big killer over time with flat mounted radiators as the up/down forces from driving offroad would now be acting from the front/rear of the radiator bars potentially causing metal fatigue and cracks. Also, now there will be no convective heat flow in the radiator due to everything being flat, but as long as the coolant flow and air flow is properly maintained, then it shouldn't matter too much.

My thoughts:

• Use a standard aluminium radiator from a Falcon or similar with decent fans and shrouds from the get go.
• Mount radiator flat or at a slight angle to help with bleeding air out.
• Use some sort of spring mounts to reduce vibrations and hard knocks from bouncing when offroad.
• Have a separate filler/expansion tank from the radiator up high to reduce air locks in the system.
• Make a good shroud so that fans pull a decent amount of air upwards through the radiator & have a scoop type arrangement on the lower side to prevent mud & stones hitting the radiator
• Move the water inlet/outlet pipes to the sides of the radiator tanks (instead of the rear) to make water pipework neater and flatter
• Have dedicated air bleed points at the highest part of engine(thermostat housing) & radiator

This is a custom made aluminium radiator with the inlet and outlet ports on the same end of the radiator. A dedicated air bleeding point is on the other end of it.


This is a very rough setup of what I'm thinking to achieve.


A pressurised expansion tank similar to what I was thinking to use. This will be mounted at the highest point in the system.

[lax2wlg]

God look at those shitty single C-section frame rails on the Chevrolet. Talk about cost saving measures.

[klompy]

If you have plenty of space would big be better or even go huge as in small to medium size Truck radiator, just a thought.

[Mehrts]

I've got plenty of space to play with, but I'm also wanting to move my fuel tank up out of harms way so that will decide how much room i actually end up with.

Just trying to use up some space that is otherwise wasted at the moment.

[slide]

Sounds like you've put lots of thought into it. Weight of full radiator on its side (especially over bumps) could put a lot of strain onto a radiator made for vertical mounting. I'd suggest an alloy radiator for this? Would be easier to fit horizontal hose tails too. Would also loose the forced air at open road speeds- you'd want decent fans and ducting, although this needed for high load low speed 4x4n anyways...
A brace system on radiator rubber mounted to chassis to reduce fatigue cracks?
Angling system to bleed air could be done by parking on a hill
Header tank at high point a great idea

[derk]

if its a road truck you're going to struggle with air flow to keep it cool at highway speeds, if your going to mount it flat there should be no reason you cant mount it on a bit of an angle so it can operate in the way it was designed to work and wouldn't make it as hard to bleed the air pockets out, go for the biggest radiator you can fit you can pick up fully welded chev or ford v8 19x33 inch alloy radiators pretty cheap these days, try and use as much exhaust tubing (or $copper$ pipe if you can steal it off your plumber mate) it helps dissipate heat and reduce coolant temp where rubber hose insulates and helps the coolant maintain higher temps, shroud the radiator and don't use those useless electric fans from super cheep get some decent fans off an aussie 6 cylinder or big euro car from pick a part or whatever scrap yard you have where you are, if you use twin fans make sure they both run together so you draw air through the radiator core and not through the other fan that isn't running and be carefull how you mount it if its between the chassis rails there can be a lot of chassis flex so make sure the radiator has good flexible mounts or it'll start stressing and cracking pretty quick, personally I wouldn't mount a radiator flat or under a deck but that's your call

[mudlva]

a mates got his rad flat and he keeps his ls1 nice and cool

its a alloy unit about the same size as a vx80 or y60

his fans blow the air downwards with the fans mounted above, with covers to keep it clean

he didnt change the rad ports but is running a electric water pump which makes it easier to bleed

[Mehrts]

Thanks for your input Slide, Derk and mudlva.

Intention is to stay well clear of cheap shitty cooling gear. Falcon radiator is the pick of choice at the moment purely for it's original application (big 6-8cyl with Aussie heat) as well as having a decent shroud/fan setup that moves a lot of air.

Yea this is going to be used on my road going Bitsalux, however it doesn't see too many road miles. I'm sick of having to clear out the radiator of mud and a couple of months ago I had the luck of a branch smashing the bottom tank backwards so the fan had a nice encounter with the rear of the radiator, so that one was a write-off.

When at road speeds, I reckon the fans would be able to move sufficient air through the radiator to prevent overheating. Also I plan on having a scoop type arrangement underneath to stop stones and things smashing into the fins. This should help with air flow as well.

The temp & pump control gear I can work out no worries it's just the actual mounting of the radiator that I'm curious to hear about.

At this stage I'm just bouncing the idea around a few people seeing who has done what and what their thoughts are.

[churchill]

I think the previous model hiace vans had flat mounted radiators. Check them out for a system to copy.

[klompy]

Had a super custom Hiace that had 2 radiators and I think it was an option for hot climates. Have a look at some of the hydraulic radiator fans they seem to be pretty grunty.

[Mehrts]

Interesting to hear about the Hiace van setup. Thanks.

[De-Ranged]

I would suggest an Y60 rad its about the biggest i could find... go with an aftermarket one with a thicker core.... this will give it a bit more strength to the core, the fill tube could easily be turned to work, it also has a good frame supporting either side of the core
Mount the radiator into a frame that supports the tanks and the core support frame.... springs and all that seem like alot of work, to be honest I don't think its needed.... the amount of water that is in the core (weight) isn't that great, I think a soft rubber inside the frame to spread the load and soften shock loading would be ample

I would be cautious about dismissing the effects of convection... its alot more than you think, helped one of the Welly boys sort a cooling issue on his lexus buggy having the hot come in the top was the difference between running happily and only running for 5 min's thats why I suggested the Y60 rad... if your on a budget try two radiators and "T" into both, done this on a rear mount behind the cab of a lexus ute that is a daily cost $40 for another rad and he has no problems at road speed

[tweake]

I think the previous model hiace vans had flat mounted radiators. Check them out for a system to copy.

your not thinking of the flat air con radiator. common in hiace, surf etc.

[slide]

Some of the hiace supercustom vans had a second horizontal radiator above (?, may have been below?) the horizontal A/C radiator. I'd completely forgotten until seen it mentioned above

[mudsurfv6]

Has anyone tried running a radiator that is mounted horizontally (flat)?

james, have you done this yet? did it work? instead of front or as well as?

was thinking about a second radiator in back of surf when I cut it down to double cab, but not enough room, so now been thinking about a second radiator mounted in/on exo above the roof, horizontally, protected by bars and mesh. big whichever factory radiator and fans. out of the mud.

would/could it work? too high? would the pump handle it? or electric pump? through roof radiator first then front? fans on top or below?

[sirLachlan]

Xr6turbo radiator fans are the business . Oem rated they keep 270 kw under control .

A fan set up to pull air will cool a radiator 50%better than the same fan set up as a pusher .

A few 1uz motors came with oem hydraulic powered fans . Could scrounge some of those fans to get serious .

I'm not sure what motor you have but keep in mind every kw of power you have is also a kw of heat you have to lose out the rad

[mudsurfv6]

I'm not sure what motor you have

1996 vzn185 surf. 5vzfe. TRD supercharged 3.4 v6. URD piggy back computer. will be putting headers and free flow muffler and 3" pipe on. with all the small mods as well read they are capable of 230kw. not sure if mine will be that but hopefully as close as possible.

was thinking of keeping front radiator and just adding in another one. so when front/air con radiators fill up with mud still got secondary one cooling. when enough air flow secondary fans ( or even viscous) won't even need to go.

A fan set up to pull air will cool a radiator 50%better than the same fan set up as a pusher .

will pull, but if fans are below radiator there won't be much room between fans and roof. would that matter? do they need room to get rid of air behind fans? and don't want to heat roof up too much from hot air behind/below fans.

or would fans on top be better sucking away from roof? that's the way I'm leaning now I'm thinking more about it. then the hot air behind/above fans will disappear up. as long as there is enough air between radiator and roof for fans to suck through.

is height above motor an issue? would an electric pump solve that? as well?

[Crash bandicoot]

Planning to do this to a long wheel base pajero double cab ute chop with a firewall behind the two front seats. C pillar will just be rollbar with mesh and a weather tight firewall behind two front seats so back doors will basically be access to storage for tools recovery gear etc. Remove the big arsed sunroof that 900x900 and mount radiator flat just inside the roof line with a header tank with pressure cap as the highest point. Fans underneath drawing down into the compartment and a couple of wide but low forward facing scoops to ram through the radiator when travelling at speed. ....think it'll work in theory. Lol.

[mudsurfv6]

Planning to do this to a long wheel base pajero double cab ute chop

keep the front radiator as well or roof radiator will be the only one?

you reckon factory water pump would push up that high or use an electric? as well?

[Checkerhead]

So, two years down the track, did anyone do this? How did it go?

EDIT: I see some of this thread is only a few months old, still, any updates?

[mudsurfv6]

I see some of this thread is only a few months old, still, any updates?

haven't decided yet, but have to soon cos when body chop is finished i'll be starting on deck. still debating if its a good idea to put on roof
issues are - weight up high when vehicle is already higher than I planned.
- pumping coolant up that high
- if leaning against tree or bank exo could flex and that's not so good for radiator
- maybe something else I hadn't thought of

[Crash bandicoot]

Planning to do this to a long wheel base pajero double cab ute chop

keep the front radiator as well or roof radiator will be the only one?

you reckon factory water pump would push up that high or use an electric? as well?

Loose the front radiator altogether.

As for flow what goes up must come down so it won't be doing anymore work then it already was....that's the theory almost every diesel locomotive on the planet has horizontal mounted radiators so it must work when ya trying to cool down a 48 litre v16 twin turbo two stroke engine of that size.

[mudsurfv6]

not sure if I will go roof or rear yet.

Loose the front radiator altogether.

roof would get enough air flow but what about if it ended up in rear? looking/reading about rear only radiators they don't get enough air flow to keep it cool on the road. don't really want to have to put a scoop up top.

[Crash bandicoot]

The boys in the club with rear mounted rads can go hammer n tong for a short while before heat saturation point they have to have there fans on pretty much constantly unless idling around (4.0&5.0 litre v8s though.) Due to the airflow around the cab...bit like following a truck on the road when the vacuum created by the mass cutting through the air. This is the issue I'm trying to avoid as I want the paj to be road legal and travel at road speed hense roof mounted

[mudsurfv6]

yeah that's what I've been reading.

some of the road legal mud bog guys in the states run it through the front radiator then through the rear under deck radiator then back to engine, using stock pump, which is what I've been thinking of. either horizontal under deck or vertical behind cab will be stuff all air flow, but would be secondary to front one. PLAN A if room....

or was thinking of roof. but

issues are weight up high when vehicle is already higher than I planned and if leaning against tree or bank exo could flex and that's not so good for radiator

so mounted to roof of body instead of exo would solve the flexing issue. PLAN B.

just thinking out loud........