300TDi radiator

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Originally Posted by uninformed

Tank, AFAIK, the specific reason for modding it is to force the water/coolant to flow through the radiator as designed....think of path of least resistance, and that big hole.

Water needs to flow through all of the radiator and at a set rate for it to cool, to fast and the heat will not get the chance to disapate out of it, AND worse if its only using 50% of the radiators area.

This is what I have been told and have done on my truck. When I contacted A local radiator mob about a new core, they recommended RedBack and also recommened doing the internal work, with out me asking about it. They said it is common to do on these Landies.

There are some things LR get right and do well.....cooling is not one of them.

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See Fella's, I have got to wonder why Land Rover engineers figured that this mysterious hole was placed where it was and why that size. My local rad bloke said LR knew what they were doing and he had seen the results of others blocking this hole, he didn't elaborate and as I said was willing to blow a job as he would not do it.
I believe there must be an explanation for leaving standard and for modifying, but so far no reasonable reason for modifying, uninformed your theory makes sense, BUT why did LR build the radiator to these specs, they would certainly have some idea of how they wanted the water to travel through their radiators, it is not as if they didn't intend for their vehicles to used outside of the UK, quite the contrary.
Any Land Rover Engineers out there that can explain, I have never had a cooling problem, my temp. gauge never goes above a quarter, the only time it got hot was after the head gasket blew and pressurised the cooling system, Regards Frank.

Frank, one of my old mates is an ex-Land Rover Australia engineer and in his opinion he couldn't work out why Solihull did a lot of things ;)

Things like the greased wheel bearings with two piece axle flanges so that you get fretting corrosion, the undersized rear lower trailing arms, the terribly undersized steering arms with a channel under the diff so that when they bent they jammed, th etime it took to introduce the cross drilled input gear in the LT230 t/case, etc.

He said Australia used to ask for changes and the UK was deaf to any request.

I can understand needing a bleed in the divider, but does it need to be so big ?

When I mentioned blocking it to my rad bloke he straight away said he used a 1/8" hole,
I'm happy with that.

A 1/2" or 5/8" or whatever it is hole seems crazy. I'm sure someone had something in mind, but what ?

I can see it helping if you have a major blockage in the tubes from garbage, but what about those of us in warmer climes that keep our cooling system clean ?

Blokes such as Pat303 have had the bleed closed for years and his car has clicked over 400,000km now.
I'll send Pat a PM and ask him to put in his 2 bobs worth on when and what he's observed although I think he's in the middle of a house move ATM.

Back when i was working on race cars an old mechanic said to me "just because the bloke that designed this designs F1 cars doesn't mean he knows what he's doing"

It really made look at things critically and try and understand what they were trying to achieve, but not be afraid to modify something either.
Luckily I worked with my ex-LRA mate quite a bit too and his attitude was much the same and we had some pretty good results changing things a long way from stock.

Tank if your running a LR temp gauge then you don't know what temps your engine is seeing.

I see where you are all coming from, but as I have never had overheating problems and I do most of my driving off-road in 4WD, I only travel up to 10 klms on tar to get onto firetrails then clock up a few hundred k's, so most of my driving is heavy duty.
I am thinking of swapping to a V8 rad. because I have a TD5 I/C that I can fit.
I agree that engineers don't always get it right, but as my rad stands it works perfectly fine, all I need to know is, that if there is a Benefit from this mod, what is it, does the motor run cooler or last longer, I will go and see my local rad bloke and see if I can get his view on it, will keep you posted, regards Frank.

like you say Tank, why is it there?? Could be for 2 reasons, 1 for the engine to get up to temp quicker, especially in Europe. And 2, when the rad gets blocked somewhat, it still allows coolant flow. Now the second seems stupid to me, as why not design a better radiator/cooling system to begin with....but it would not be the first bandaid LR has pulled out of there bag of tricks.

IMO, even though LR supposedly test in the desert for high operating temps, it is clear by the collective evidence that the 300Tdi cooling system is marginal at best when in full working condition. By this I mean for all tasks the LR is designed to do in our Australian enviroment.

As far as you doing mostly 4wd and that being hard on the cooling system, I would say from my experience that, that be the opposite. Having spent the day (a good 8hrs) 4wding around my mates property out west, in high 37+ degree heat, doing upto 70km/h on dirt tracks and lots of low range work, my engine never even looked like getting hot (VDO gauge with much better reading than LR) and this was before I cut the hole in my left gaurd to exhaust engine bay heat.

but drive on the hwy and incounter a climb like the little toowoomba range and my temp goes from 87c - 100c , that with no load on or in my tray back 110.

I think its good you question something rather than just join the flock, and at the end of the day you have to do what makes you warm and fuzzy.

I will say that a stock rad that has its cooling system regulary serviced and rodded every timing belt replacement is going to fair better than one that is modded and not looked after.

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Originally Posted by uninformed

As far as you doing mostly 4wd and that being hard on the cooling system, I would say from my experience that, that be the opposite.

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I second that.

The weekend just gone I did a few hours 4wd'ing in low range. Up hills the factory temp gauge sat in its usual half way point not telling me much of course, but it didn't take much of a downhill or easy flat stretch and the factory gauge started dropping slightly off the half way point. This says to me I was far from pushing the cooling system on a few uphill stretches in low range 3rd. If I sit on 110 on the freeway for a while, it takes a lot of slow/stopped/idle time to get the factory gauge to drop from half way afterwards.

It makes sense when you think about low-range gearing. It seems hard to imagine that's working the engine as hard as hi-range 5th.

VDO temp gauge at home ready to fit - just didn't get time before the weekend, so I can report back with better stats next time.

After rodding a radiator I am thinking that there are two more processes that should be done, that is immersing the core in a acid bath to get rid of the remaining built up alkaline plaque and then after the tanks are replaced a thorough pressure test must also be completed.

Those over sized bleed holes may help in the interim to allow faster warm up times, so reducing the bleed hole size ( as I have had done with the now spare radiator from 'Fred' ), should help keep the radiator circulating it's coolant through the tubes as the radiator looses it's efficiency while the plaque builds up again.

The test will come when after I have rebuilt my Defender, I intend to use that spare radiator from the Discovery.

Some interesting discussion about using vinegar on this site.

Disaster How to clean WC radiators? - bit-tech.net Forums

Isn't it phosphoric acid that the radiator repair places use, and what is the effect of doing this when compared with aluminium and copper cores?