Radiator Modification

The original radiator was steadily leaking, and to be brutally honest, didn't actually work very well anyway. It was also a pig to bleed because Tiger (in their infinite wisdom) never bothered to put a bleed screw into their radiator. The options were to fix my current one, or find a replacement. Since I'd already had two goes at fitting bleed screws myself, this was going to require a radiator specialist, just to stop a badly designed, inefficient radiator from leaking. It wasn't however, going to make it work any better.

So, the decision was made ... time for a new radiator. However, nice though they are, custom made ally radiators are just too expensive, so I needed to find an "off the shelf" solution. A few questions on the Tiger Owners Club forum revealed that several people have managed to fit a Polo radiator (which is small, light, and all-ally) into their Tiger Cats. Unfortunately, no-one seems to have tried to fit one into a Six. Fortunately, Neil Wain had a Polo radiator waiting to go into his Striker build, so I was able to borrow it for a week to test fit it. The results were promising enough for me to go out and buy a nice shiney new one from German, Swedish and French (part number 17321B, good value at £50 incl VAT).

So, I'm now at the stage where I'm mocking up the position of the radiator with anything that comes to hand (bits of wood, kitchen roll holders, etc) in readiness to start making the brackets to hold it all in place. I've proved that it will definately fit, but I need some extra metal to make the main bracket (another trip to Metal Supermarkets in Southampton), some new radiator hose, and bunch of hose connectors and T-pieces. The new position of the radiator also means that the existing fan is even less useful than it used to be, so I'll need a kenlowe-type fan from somewhere.

Anyway, here are some thumbnails showing the location of the radiator. This all fits within the bounds of the nosecone, though its an extremely tight fit. Click through to get bigger pictures (about 1Mb each). As you can see from some of the pictures, the bottom of the new radiator sits quite a bit higher than the old one, so there will be quite a gap underneath it. I'm going to add some baffling to ensure that the airflow is directed up through the radiator, and at the same time fashion a mounting bracket for the air temperature sensor for my Emerald ECU so it sees the fresh air, rather than the hot stuff that's been under the bonnet a while.

Radiator a Radiator b Radiator c Radiator d Radiator e Radiator f Radiator g

Update 1: Mr Angry-Grinder had a brief session with the original radiator mounting brackets today. Interesting to note that the powder-coating has started to bubble and flake. I think I'm going to need to remove a lot of the powder-coat from the front area of the chassis, and repaint it. Another little task.

Anyway, I then added some new brackets to the front cross-member with the new rivnut setter that I picked up at Stoneleigh. Luckily the scrap I used to make these brackets was pre-slotted, which allowed me to easily make the ally angle that runs under the new radiator adjustable fore and aft, in case I've not got the measurements exactly right. I also shortened the top bolt on the front nearside lower wishbone mounting. This will make it much less likely to foul the bottom hose where it enters the radiator.

Radiator h Radiator i Radiator j Radiator k

Update 2: Just got back from a (very pleasant) holiday in the sun, and spent an hour this afternoon finishing off the mountings for the radiator, and checking everything still fits as it did during the test fittings. Fortunately it does. But there will be no requirement for any baffling around the radiator to direct the airflow - there is sod all clearance in there now!

The first picture shows the nearside bracket from the top chassis rail, which extends forward to what will be the upper mounting point on the rear of the radiator. The rear mounting points are exactly the same as the front ones, which you can see clearly. These are normally used to attach baffling, which directs the airflow through the radiator, but I'll just use the top pair on the rear as attachment points. The second picture shows the whole of the front of the car, with all the brackets in place, but the radiator removed for clarity. You can see the angled holes cut into the main bracket to accept the mounting lugs on the bottom of the radiator.

Radiator l Radiator m

Update 3: Before I left for the holiday I ordered some radiator hose "off the reel" from Arco Ltd, but after some 3 weeks they still hadn't produced anything, so I cancelled it and went looking elsewhere. The Southampton branch of Hyphose Ltd came up with the stuff I needed off the shelf when I visited them on spec. I'd highly recommend them as a supplier - they were friendly, helpful, and very tolerant of my questions when I clearly didn't know much about hoses! Ended up with some 90 degree bends, and a meter of 32mm hose (which in the end I didn't need to use).

Straight hose joiners were made up from some cheap 32mm O/D aluminium tubing. These should survive better than the steel ones that Tiger originally used, which were corroding quite badly.

Mr Wain kindly come up with a 32mm / 19mm / 19mm / 32mm joiner (a Tiger item for a Zetec install in a Six) from one of the many stashes of useful bits that he has tucked away in the back of his garage. Cutting this in half resulted in two 32mm / 19mm / 32mm joiners, onto which I squeezed the 16mm hose from the bottom of the expansion tank (thanks to boiling water and liquid soap!) and the bottom hoses. I also ordered a budget kenlowe-type fan from Stafford Vehicle Components (SVC) Ltd, along with a Pacet "through the radiator" mounting kit. The Post Office messed up delivery (ie, still hadn't after 2 weeks), but SVC made good and resent the order via courier. Again, a highly recommended supplier, simply for their excellent customer service! My local VW dealer ordered in the thermostatic switch gasket and a pair of their self-tappers for the radiator, overnight, for a grand total of £1.80. Can't complain at that.

Radiator n Radiator o Radiator p

The expensive purchase was a custom-made joiner, allowing me to connect the 20mm take-off from my remote thermostat housing, to the 8mm hose to the top of the expansion bottle, and the 8mm hose to the top vent on the polo radiator. Not cheap, but does the job nicely.

I also reworked the loom at the front of the car to replace the switched live feed to the thermostatic switch, as the original wire had oxidised so badly that it couldn't be soldered, which meant that I couldn't extend the lead to the new switch position. Since I had the whole loom open to do that, I also moved the drop of the thermostatic switch wires from the offside to the nearside of the car, simplifying the layout of the wiring loom.

Radiator q Radiator r

The only problem I experienced when fitting it all together was with attaching the top and bottom hoses to the radiator. Because there is no room to mount the radiator vertically, the inlet/outlet both point downwards by about 30degrees or so. Combined with the position of the chassis rails, this makes it impossible to attach straight hoses to them. Instead I needed to graft on some offcuts from pre-formed curved hoses, to get them pointing in the right directions. Not difficult, but definately fiddly.

The system takes about 7 litres of coolant, and self-bleeds properly, if rather slowly. So, just pour the coolant into the expansion bottle, and eventually it all works its way down into the system. Air bleeds back out via the expansion bottle. Once the engine has been started the system warms up quickly with the thermostat closed. Once open, the system stabilises on the temperature set by the radiator thermostatic switch. The fan / radiator combination seems to be very efficient, with the fan only running for 20 or 30 seconds at a time, but still showing a noticable drop on the temperature gauge at each run.

Annoyingly, I seem to have a very small leak, bizzarely from one of the hoses that I didn't mess with. I guess I must have disturbed it while working on the others. It's pretty minor, but something to fix (probably just with a new jubilee clip) next time I have the car drained down. While thinking about that it also occured to me that while I was reworking all the plumbing I really ought to have added a drain point to the system. For example, adding another T piece into the bottom hose, with the T blocked with a bolt, would make draining the system down a much easier, less messy proposition. Again, something to fix next time I drain the system down.