Archive for the ‘Cooling Systems’ Category

Because of the confined workspace, there are a few tasks that have owners groaning and rolling their eyes when their Classic Mini needs work in these areas.  A big one that I have to do on my own car is the steering rack.  I’ve had the typical banging noise under the toe board as the car rolls over bumps and I can move the front wheels against the steering arms and see and hear a bit too much free-play!  The steering rack was about the ONLY thing I did not change as I restored my 66 Cooper S from the body shell up.  It seemed fine and the car only had about 50.000 miles on it.   Still, when you consider that you can change the rack in about 10 minutes on a bare shell, and how cheap the replacements are, it’s very much a false economy to hope that it’s fine!

Now, I have to at least drop the front sub frame a foot or so, and while not terribly difficult, it can be a bucket of worms as I’ll have to separate metal brake lines, clutch hose, shift linkage, engine stabilizers, some of the wiring harness, the exhaust system, fuel plumbing…. I’ve about talked myself out of it just thinking about all the things that could get stuck and make the project bigger!  The good news is that the steering rack and tie-rod ends are usually in stock and not at all expensive… here’s the close-ratio LHD unit for my Mk1:


Another notoriously maddening area to work on is the radiator.  Most models are a very tight fit to the fan and the surrounding sheet metal. But it’s ether try to finesse it out,  or pull the whole engine out WITH the rad!   The good news here is that we’ve scored a good buy on the most common radiator, and are passing the savings on to you…. a NEW rad for less than the cost of cleaning out an old one.  That should lessen the pain of banging up your knuckles to install it!


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As reported on the Mini Mania Community Forum

So, my car is getting too hot so i decided to flush the system, got it normal temp drained it, green brown color..im guessing rust and coolant. let it cool then refilled with clean distilled water, warmed it up, drained it, slightly cleaner. i did this about 4 times until it ran clear, filled it up again and put in about 1/3 pint super coolant(green version of water wetter). its doing a little better but still getting a little warmer then what i would like. does anybody have anything that works well for them??


My method of flushing typically involves me taking off the top rad hoses, rad cap, thermostat, and heater valve hose.  Then I take a garden hose and blast inside the radiator from both openings on top, and I’ll blast directly into the head through heater valve and where the top rad hose would connect into it.  Then blast the line going to the heater core.  Depending how you hold your hand over open lines you can get more pressure to different parts of the system.  Eventually the brown stops coming out and you can flush it out with distilled water and go from there.


Some of the parts houses sell a two part cleaner, i have used it before and it will clean the cooling system but it can also cause problems if your cooling system, freeze plugs or head gasket are very old it can eat away scale, rust, etc


I made a little adapters out of PVC pipe and fittings that allow me to plumb garden hoses directly into the top and bottom hoses. Works a treat. Will take pics if I can find them (it’s been a while).


As a footnote to your question about flushing and concerns about running hot….

Do  NOT assume your temperature gauge is accurate.  Get an infrared thermometer and check the temperature of the thermostat housing and the top tank of the radiator.  It’s not at all uncommon for Smiths gauges to be inaccurate.  I have a new radiator in my project Spitfire because the previous owner had disconnected the gauge’s voltage stabilizer which made the gauges read way hot.  Check the cheap stuff first.


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Radiator removal and reinstall tends to depend upon the two Ps: Patience and Pain threshold! This is especially true with the Mk I and II cars that still have the inner radiator shroud as part of the inner wing panel — like your car.

I’ll describe what works for me on the early cars. This process depends upon the correct parts being on the car (e.g., no fan bolts that are too long) and the fan being installed the correct way ’round!

1. Remove upper hose and upper radiator to thermostat housing bracket .
2. Drain water.
Remove radiator cap. If you still have a radiator with a drain tap this is easy and not too messy if you hook up a bit of hose to it. Hoses of the right size can be found at auto parts stores, good hardware stores and pet shops (if they sell fish tanks!). If all you have is a lower bolt in place of the tap, still not too bad. If you have neither, there is no other way than to make a mess. I remove the lower hose from the water pump. A drain pan will catch a lot of the water but you’ll end up using strategically placed towels, too.Mini Cooper radiator assembly
Caution: this is all best done when the engine has cooled off!
Remove the heater hose from the lower hose take off. A variation is to remove the heater hose at the lower hose connection before removing the lower hose from the water pump.
3. Remove upper radiator shroud.
If the hex head sheet metal screws are original, they are 1/4″. Buy a proper box end wrench, or, if you have an “ignition” wrench set, there will be a 1/4″ in there. The front two screws and the upper back one are not hard to get to. The wrench works well for the middle one on the back.
Don’t worry if you drop a screw or bolt or lock washer or two. This is one area of the engine compartment where the hardware hiding gremlins do not reside. Once the assembly is out, you’ll be able to get to anything quite easily that you dropped.
4. Remove the grille. (Grille buttons are nice!)
5. Jack up the front of the car and support it properly.
6. Remove the two lower shroud to motor mount bracket bolts. 5/16″ fine with 1/2″ head.
The front one is not too hard to get to through the grille opening. Easier to use a ratcheting box end wrench.
The back bolt — if still in place — can be reached through the grille opening or the inner wing panel inspection hole via the wheel well. (Tire removed makes it easier.)
The reason I commented on the back bolt being there is that a common “trick” is to just leave it out upon reassembly. Either I’ve gotten better with practice or I’m more patient or both, but I put them both back in now days. Usually you can get away with leaving it out, but there are occasions (bent shrouds, using a tropical fan, etc.) where it is needed.
Note: this step can be left until after the fan is removed. Some find they can get to the fan bolts a little easier if the radiator assembly is unbolted first. I seem to do it either way.
7. Remove fan.
Loosen the generator to take tension off of the water pump pulley.
The four bolts are 1/4″ fine with a 7/16″ head. Either a long handled 7/16″ wrench or a ratcheting box end 7/16″ will work best. I prefer the later. If you have neither, use a standard box end and test your pain threshold by scraping the backs of your knuckles on the radiator fins. Then buy a better wrench for next time!
This step saves a lot of time, BUT it depends upon the correct length bolts being in place. If someone has used ones that are much too long, you may not be able to back them out far enough. Then you have to go to Plan B and remove the lower shroud, then the radiator — not my preferred way of doing things…and a topic for another email!
If the fan is a metal one getting the bolts out is a little bit harder. If it is on backwards — don’t laugh, I see it all the time — it is even harder. The plastic fan as introduced around the time of your car is easier to work around. If you have a tropical fan (6 big blades) it is a little bit harder. If you have a tropical fan on backwards, I’m out of town the day you call for help! This situation calls for removing the lower shroud and using a few choice words.
8. Remove radiator
The radiator with the bottom hose still attached and the lower shroud still attached should lift right out. Don’t forget to keep it upright until you can drain the rest of the water out!

Part II. Things To Do While the Radiator Is Out
1. Radiator repair
Take the radiator to a good shop and have it cleaned and pressure tested. If you don’t have a drain tap in the rad, have one installed.
2. Lower bracket bolt holes
Remember taking out the two 5/16″ lower bracket bolts? Make sure they have good threads and that the threads in the holes are in good shape. Getting the bolts back in is a bit of a fiddle so you want to make sure they are going to go in easily by hand as far as they can. I replace them and the lock washers with stainless steel.
3. Replace the lower hose, if necessary.
The hose goes back on the radiator before the rad goes back into the car.
4. Consider replacing the water pump, bypass hose and fan belt.
5. Consider replacing the motor mount.
6. If you’ve thought about replacing the front brake hose or working on the upper suspension arm, now is the time to do so when everything is easy to get to.

Part III. Radiator Installation.
1.  General Preparation
Make sure all the threads on bolts and bolt holes are clean, and trial fit any fasteners to make sure you don’t have any problems getting things together later. I usually replace all the hardware with stainless steel and I still use a little anti-seize compound during reassembly.
Get out whatever magnetic pickup and/or clamping pickup tool you prefer. You’re bound to drop at least one bolt or lock washer, and you may find them tucking into places that you can not get to by hand. A favorite to drop is a fan to water pump bolt.
Take a look at the four radiator grommets. Two on the radiator to thermostat housing and two on the bottom shroud bracket. I should have mentioned these in Part II. Replace, if necessary.
Put the water pump pulley back on the water pump and align the holes of the two. It’s easier to do now when you have room to see the hole alignment. If you have a very short 1/4″ fine bolt, use one to keep the two aligned. You’re bound to knock the pulley about before you’re ready to install the fan. Oh, I forgot to mention the fan (if plastic) as one of those items to replace if the vanes are bent back from pushing all that air.
Hang the fan belt. Don’t forget this step!
2.  Radiator preparation
So the radiator has been cleaned, flushed, pressure tested, a tap added and maybe painted. Now, put the bottom section of the shroud on leaving the upper two screws a little loose.
Install the lower hose. Make sure the clamp is such that someone looking down from the top of the radiator would be able to get a long screw driver on it…just in case.
3.   Drop the radiator/hose/lower shroud assembly into place.
At this point there is the option of bolting the bottom in place or installing the fan next. Not much difference on a car with the inner fender radiator shroud built in, but it’s probably a little easier to get the fan on first.
4.   Install the fan
If you had a bolt holding the water pump pulley in place, remove it carefully so you don’t get the holes out of line.
Insert the fan, with any applicable spacers, the right way ’round (the fan center should cup around the pulley) and carefully slide a bolt with lock washer through the fan, spacer(s), pulley and into the threads on the water pump. Work the bolt in by hand or wrench a ways. Rotate the fan and install the other three bolts.
Getting the bolts in place will test your dexterity if you do it by hand. It gets a little easier with whatever favorite locking type pliers or needle nose pliers you use. I use medical hemostats! These are great for jobs such as this (and motor mount bolts). I’ve been able to find them at various car shows in the swap and shop area. There always seems to be someone at the bigger shows that buys up old medical and dental equipment (dental picks come in handy, too) and sells them cheaply.
Once the bolts are in place, tighten them up. I use the same ratcheting 7/16″ box end that I use for removal. Makes the process easier.
5.  Install the upper shroud.
At this point I modify the upper shroud by slotting, vertically the back lower section from the edge to the hole. This is so the upper section can be slid down and onto the partially installed screw already in the bottom section.
With the radiator still not bolted down, you have a little more room to work on the back machine screws.
Slide the shroud down onto the radiator so that the back, lower (now slotted) hole lines up with the machine screw. Remove the front screw loosely holding the lower shroud’s upper end in place, line up the holes and insert and tighten the remaining shroud screws. I don’t slot the front like the back, preferring to keep things looking standard, but it could be done. Really not necessary. The time saved is negligible at the front where you have good access.
6.   Install the two lower bracket mounting bolts.
This will take some patience and dexterity, but it can be done working through the grille opening and the wheel well. The front one is probably the easier and can be gotten to through the grille opening. You can leave the back one out if you get seriously frustrated. There’s little chance it will be a problem, but why take even a little chance?
7.  Hook up the lower hose.
With a clamp in place (and positioned so you can get to it!) slide the lower hose onto the water pump and tighten the clamp.
I bias the hose a little so that the heater hose take off is leaning slightly away from the header/head junction just to make sure it doesn’t cook itself on the hot exhaust.
8.  Hook up the heater hose.
If you have a left hand drive car, watch the routing of the throttle cable in relationship to the heater hose. You may route the cable so that the heater hose helps hold the cable away from the exhaust manifold. It depends upon your particular set up.
9.  Reinstall the upper radiator bracket.
Don’t tighten the thermostat housing end nuts down all the way, yet.
Rotate the fan to make sure you have clearance. If it clears, tighten down and check again, just to be sure,
If you don’t have clearance, you have some wiggle room at the thermostat end and even the two dreaded bottom bolts. Almost always that is enough. If not, you may have a shroud that is bent a bit and will need a little leveraging.
10. Reinstall the upper radiator hose.
11. Tighten the fan belt.
12.  Fill the radiator.
Make sure the heater valve is open.
Start filling the radiator with your favorite fluid mix watching for leaks. Stop and let the water settle occasionally, and don’t overfill.
Run the car getting it up to temperature. Continue checking for leaks, and watch the water level in the radiator. It’s likely to go down as any trapped air works its way out the open radiator neck. Top up, put on the cap and go for a drive. When the car cools down, check the fluid level and top up, if necessary.

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