Another 46 to 47 project!

[jbcollier]

Please post photos of the relay wiring, the red fan ground point, and the wiring at the rad fan switch.

[DreamsOfA47]

The rain has stymied me here in SoCal so I'll snap some pics as soon as I can. I haven't touched it much in the last 48 hours due to the poor weather. Currently, after much fettling, I have now managed to somehow wire the fan to be on when the ignition is turned switched on so that's a much better situation than it never coming on! Taking advantage of about an hour of sunlight yesterday I drove the car around the neighborhood and it still runs way hotter than it should. With the fan it gets less hot than it did and it takes way longer to get hot, but nonetheless it overheats eventually. I've seen previous threads that I will have to search for again about a Chinese alloy radiator that seems to work well. I hate buying Chinese products for fear of awfully poor quality but a bunch of you seemed to vouch for it and I think that's sold me on it. I can't afford a $1300 radiator from RD right now, but I'm starting to believe that my old copper radiator is simply old and worn and not cooling as well as it should.

[bjthomp]

Have you considered having your radiator re-cored? At one time that was standard procedure. It will reduce your anxiety about Chinese quality, save you some money, and you'll end up with a radiator that fits properly. It's important if you go that route (re-coring) that you get the appropriate fins and tubes and the baffle in the inboard tank is installed properly. Years ago, I had an S1 radiator re-cored with fins and tubes used in police cars and it works great. 

[jbcollier]

Copper is insanely expensive.  An aluminium rad will be much cheaper.  Get a “thick” one and without a fan as the fan they provide is always sub-par.  Fit the largest (usually 11” will “just” fit) and highest output you can get.  I almost exclusively, and happily, use Spal fans.

[jbcollier]

“It’s overheating”

First off, how do you know that?  Is the gauge reading high?  Or, is the coolant actually boiling? The most common cause of “overheating” is a gauge malfunction.  Usually a failed instrument voltage regulator causing the gauge to read high. Use an IR thermometer and check and see what the actual engine temps are (hottest next to the thermostat) — IR thermometers give a relative reading depending on the properties of the material being read.

The next most common cause is the rad fan.  Wiring, relays and switches can all cause issues.  One odd one is that it is easy to wire the rad fan to run backwards.  Instead of blowing air through the rad and into the wheel well, it draws air in.  This works ok-ish at low speeds but, as you speed up, road speed related air pressure will block the fan from pulling air through and lead to overheating.  The stock fan is also marginal at best at it s a pulled wired to run as a pusher.  Given the curvature of the blades, this results in a 30% to 50% reduction in potential air flow.

The next Europa-specific potential fault is the flow baffle in the rad.  Hot coolant from the engine flows in the bottom through the rad bottom, back through the rad top, and, hopefully cooler, out back to the engine.  There is a baffle in the side tank between the inlet and outlet.  There f this is missing or damaged, coolant will flow straight back out bypassing the core entirely.  Remove the top hose and use a bent piece of wire to gently probe and see if the baffle is in place.  You can also tell by feel.  If the side tank is hot, top and bottom, but the core is cool, then the baffle isn’t there, bent or corroded.  Should be hot at the bottom inlet, a little cooler bottom RH, cooler yet at the outlet (if the rad fan is running.

Lastly there are the usuals: corrosion induced restrictions, failing head gasket, faulty thermostat, etc.

[DreamsOfA47]

Yes on more than one occasion the coolant has boiled over and left me stranded! Thankfully I always carry a whole bottle of coolant with me in every car, no matter how old.

JB thank you for keeping me honest and helping me check all the boxes before I buy something hastily or attempt to fix something that may not be the cause of my problems! Allow me to further illustrate my troubleshooting up to this point:

Aside from being carless enough to not watch the gauge properly and letting the coolant boil over once and letting the temp gauge get close to maxing out several times now I have measured the temp at the water pump by the temp sender when the car is idling in the driveway after having freshly warmed up and it reads between 180 and 200 F, which seems to line up with the gauge reading between the labeled 85 mark and the next tick hotter; based on that I believe the gauge to be functioning properly. I have not checked the voltage regulator, but the fuel level gauge seems to also be working and that runs through the voltage regulator as well, so I assume it's fine. The oil pressure gauge appears to be faulty (pending further troubleshooting) but that could mean the regulator isn't working.

Up until Monday night I didn't have the fan working at all, but I've now wired it in such a way that it's currently always on when the ignition is on, so the wiring isn't a factor in the current cooling challenges. I'm currently running a modern fan given to me by Joji. I remember you mentioning very early in this thread that the fan is often wired backwards and needs special attention paid to it and I've made sure its both properly wired and blowing the appropriate direction to push air into the radiator and out the wheel well so I know that's not currently the case.

I did previously have an issue where I had a paper towel in the bottom rad hose blocking the radiator inlet, so I've already gone through that and can attest to the parts of the radiator mentioned being heated as described now that the blockage has been removed. In troubleshooting that I also removed the thermostat for fear it may not be functioning and I have yet to put in a replacement in order to troubleshoot with one less variable to contend with.

I don't believe the head gasket has failed as there don't seem to be any other symptoms but I've yet to look into that further. I have no idea whether or not the steel coolant transfer pipes my be corroded and had the flow restricted but I don't doubt that may be a contributing factor. I'd like to upgrade to the stainless one's from RD but I doubt I'll do that for the current configuration.  Also the old broken water pump has been replaced with a new one and its working as designed by all indications.

Lastly the temp seems to be fine on the freeway or moving at speed with plenty of airflow. The gauge sits right around the 85 C mark when driving at speed. It'll also come down from higher temps with some sustained high speed driving with good airflow over the rad, but the car still gets very hot pretty quickly (even with the fan going) at slower speeds or at a stop, so at this point I'm believing it to be the radiator being potentially 56 years old and no longer functioning as well as it should be.

Did I miss anything, Gents? Do y'all think I'm headed in the right direction with my radiator hypothesis, or should I look elsewhere?

[Richard48Y]

You mention a paper towel, so is your radiator core partially plugged from that?
Back in the good old days it was possible to have a radiator "Rodded".
This meant having the top tank removed and then each core had a flat rod run through it top to bottom.
This physically removed all old sludge, scale, or other blockage.

Before spending $$$ you might try removing the radiator and reverse flow flushing it.
Several products are available to remove internal scale/crud, from commercial to white vinegar.
The radiators are not too large, an old tote tube may be big enough to soak the entire part before flushing.
Just my first reaction.

[DreamsOfA47]

I've been concerned that there could be a paper towel related blockage. Rodding sounds like a pretty comprehensive procedure to clean all he crap out! I'm not sure if that's the route I'd want to take, though.

Here's an important question I'd like y'all to weigh in on: Is a new aluminum radiator an improvement on the copper one currently in the car? I'm not doing a restoration, my goal is to eventually build a race car out of this pretty worn car so it seems like a good idea to change rads rather than fix the old, potentially worn and maybe even clogged one. I figured if I have to drain the coolant and remove the rad anyway I may as well just change over.
Does that seem reasonable enough to y'all?

I don't drive the car much, maybe once a week the 10 miles each way up the small highway if the weather is really nice so I'm not super worried about overheating in traffic, but the fact that I begin to heat up drastically even sitting at a stoplight is worrisome. Plus I want to change out the temp sensor so if  have to drain the coolant anyway may as well do everything at once, right?

[Bainford]

Although aluminum is a good conductor of heat, copper/brass is significantly better. I recently changed out my original brass radiator for a nice aluminum one (not Chinese, but made in the USA by Saldana, a maker of quality custom race car radiators). I used the same aftermarket fan on both radiators. I was not experiencing overheating issues with the brass radiator, I just wanted to take advantage of 11 lbs less weight. With the new aluminum radiator fitted, and no other changes, my car runs warmer and heats up more quickly in slow running or traffic, requiring me to switch on the fan more frequently.

Just food for thought.

[DreamsOfA47]

That's definitely food for thought! Did your car heat up past running temp with the fan running on the old radiator? Ow did the car damage to stay cool? Also you say the alloy rad alloys the car to heat up after and the fan needs to be used more often, but does the car stay close to optional temp with the fan on? Is heating up just a Europa foible?

[DreamsOfA47]

I've been bombarding Y'all with questions about problem's I've been having I haven't shared much success with y'all. Here's a 10 second video of me pulling away in the Lotus after having finally gotten many of the major issues sorted. I think it sounds great and its been driving really well!

https://youtube.com/shorts/EU47iuHsHBE?feature=share

[Bainford]

That's definitely food for thought! Did your car heat up past running temp with the fan running on the old radiator? Ow did the car damage to stay cool? Also you say the alloy rad alloys the car to heat up after and the fan needs to be used more often, but does the car stay close to optional temp with the fan on? Is heating up just a Europa foible?

First of all, I should mention my car is a Twin Cam, for whatever that may be worth in this conversation.

With the fan running, the car would not exceed normal running temperature under any running conditions. On a hot day in very slow running or stop & go traffic, the needle would climb past 100 c. Switching on the fan would start the needle dropping in a minute or two, and would quite quickly return to the normal running temp, even without the car moving. This is true for both radiators, but the action is significantly quicker to rise and slower to drop with the aluminum radiator, and with the aluminum radiator the fan is needed for normal slowish driving on a hot day to encourage the needle hang out in a comfortable neighbourhood. I only have a few hundred miles on my aluminum radiator, but so far I have been able to reassuringly control the temp with the fan switch.

Also, it may be worth noting that when I say 'hot day', I'm referring to Nova Scotia hot, not Arizona hot.

[Richard48Y]

My takeaway from these radiator threads is that I will do my best to retain the original radiator.
Aluminum light weight is nice but summer here runs 85º-110º F.

[DreamsOfA47]

Thanks for further explaining what the temps do under what conditions! My big problem now is that even with the fan on I still have the issue of the gauge passing 100 C at a stop or slow driving but it comes back down at high speeds, eventually. Its good to know that it shouldn't do that and that behavior isn't normal.

For me down in coastal SoCal the summer is usually between 75-90 F and if its gonna be hotter it's a big deal talked about in the news for weeks so I have plenty of notice not to drive the car! 

[jbcollier]

Take the rad to a rad shop and get it tested.  Then make a decision after that.  If I had a choice between a new copper rad and a new aluminium rad, I’d chose copper.  You won’t have that choice however as new copper rads are not available.

Next, go to an auto parts store and get a kit to test the coolant for a head gasket leak.  More to come but I ‘m losing signal.