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The Moss catalog shows both a round and a square type fan motor. Is there a advantage of one type over the other?
There is also shown an after market double 10 bladed fan set up. Does it cool better than the two 4 blade original units?
I’m worried about my first Summer with my XKE here on the Texas Gulf Coast.
Last edited by mpawelek; Mar 13, 2026 at 09:34 PM.
How hot does the car run now? You probably have an IR temp gun that you can aim on the top and bottom large radiator hoses to get an idea of what cooling level the car has now. Have those hoses been replaced under your ownership? I'm sure you have also flushed and refilled the radiator to make sure that it is relatively clean. The Es have a temp sensor mounted near the thermostat.
You will want to make sure that the gauge corroborates your IR temp gun reading. The temp gauge does not inspire confidence. Typically, the needle should reside somewhere in the N_O_R_M_A_L area. This YT may provide some insight:
I don't recall if your S2 is equipped with "air conditioning". If so, it is anemic at best unless it has been throughly upgraded to modern components. These coupes can be incredibly hot to sit in for summer driving. My S2 came with factory air, I have never used it. Here in Wisconsin if it is too hot to drive the car with no 'air', then it is too hot for a 50+ year old car to be out on the road. IMO.
I put in a CoolCat radiator as well as new CC fan motors. Because the original instrument voltage regulator was old, I also put in one of those. Easy to do and removes all the guesswork as to what part could be the issue.
I have a '67 S1. I also upgraded the fan and fan motor along with the Voltage regulator. I also put in a new otter switch. All from Cool Cat. Very satisfied.
As part of the sales the previous owner had the cooling system flushed out and new fluid added. I have installed a new sending unit. From previous experience I have found that the dashboard temperature gauges can be highly inaccurate. The AC compressor was given to me in a box so it does not pertain my questions.
80F here this morning. On a brisk 12 mile drive at 65 mph my gauge shows right below the red portion but not touching. Upper radiator registered 185F and lower exit 155F so a 30F drop. I have a thermometer that fits into the oil dip stick hole at the same length and the oil registered 225F. All this looks ok but I do not like the gauge riding so close to the red portion. I have adjusted the tiny screws in the back of the gauge as well as possible.
I cannot find the “Instrument regulator” you mention in my catalog. Is it any of these units near the battery? Could someone possibly supply a link? Thank you!
PS- I drive my ‘64 356SC all Summer here but always very early in the morning and the small vent windows at the front of the doors help a lot. I also have a construction vest with pockets that holds four large frozen packets. The P car is air cooled also.
Last edited by mpawelek; Mar 14, 2026 at 02:14 PM.
This regulator is located on the backside of the drop down cluster door. It supplies both the fuel gauge and the temp gauge. Easy to install, a 5 minute job. Make sure the wires go back on the correct spades,
I can get a photo from my PC and post it later today.
Last edited by Valerie Stabenow; Mar 14, 2026 at 02:48 PM.
This regulator is located on the backside of the drop down cluster door. It supplies both the fuel gauge and the temp gauge. Easy to install, a 5 minute job. Make sure the wires go back on the correct spades,
I can get a photo from my PC and post it later today.
I looked in my gauge cluster and nothing like this is there so I will order one tomorrow.
A picture would be wonderful!
Here are two photos, the first one should help you locate the Instrument Voltage regulator. This is with the cluster door down. It's the little rectangular box that looks a lot like a relay, It has green wires coming out of it. This is at the end of the cluster door closest to the steering wheel.
The second photo shows the new electronic version in place, it's the little black unit. Be sure to verify that it is securely in place and screwed down and that you have reattached the wires on to their correct spades.
Here are two photos, the first one should help you locate the Instrument Voltage regulator. This is with the cluster door down. It's the little rectangular box that looks a lot like a relay, It has green wires coming out of it. This is at the end of the cluster door closest to the steering wheel.
The second photo shows the new electronic version in place, it's the little black unit. Be sure to verify that it is securely in place and screwed down and that you have reattached the wires on to their correct spades.
The Moss catalog shows both a round and a square type fan motor. Is there a advantage of one type over the other?
There is also shown an after market double 10 bladed fan set up. Does it cool better than the two 4 blade original units?
I’m worried about my first Summer with my XKE here on the Texas Gulf Coast.
Which fan motor do actually have in your car? The square motor was used until the very end of production. Each motor requires four studs to bolt to the shroud assembly, if you have square motors, these can be reused. It's a series-wound motor, which means it only turns counterclockwise, regardless of polarity. But here's the catch: the S1 used an identical fan motor, but it was internally wired to spin clockwise. Maker sure they send you the correct motor.
The round motors are permanent magnet motors, so they can be reversed by reversing the leads. They were used on the very last S2's and all S3's, so the new and improved version. They're a bit more powerful than the square motors, they use a bit less current. The round motors need a special mount. If your car is already equipped with them, you'll have the mounts. Otherwise, another part to buy.
If your fan motors work, I wouldn't change anything until I had experienced some summer driving.
As part of the sales the previous owner had the cooling system flushed out and new fluid added.
When I started having issues with temps on my 69 (this was around 1990 or so), I had the radiator recored by a brit specialist. That seemed to take care of everything until about 2021 when the temp was doing what yours is. At this point the recore was 30 years old and the whole assembly was over 40 years old. Opted to replace the radiator with a CoolCat unit. It was truly 'plug and play'. All the fastener holes for the support brackets lined up. The fasteners for the AC condenser as well. Just sayin'
I may be a bit paranoid because this car is new to me and I have no older records of what might have been repaired or replaced in the past. This will be a fun “day out” driver so not pushed hard or taken out more than 100 miles or so from home. For now just trying to get it safer and somewhat reliable. My health for daily work on my cars is ok but when the chemotherapy gets cranked up occasionally I live a totally different life. While having great fun learning and repairing the XKE I have to be realistic also.
This group appears to be smaller than what I am used to on the main 911 and 356 sites where dozens write in for every question but the few of you who have helped me here are very knowledgeable and kind. Thank you.
QUOTE=mpawelek;2906028]
80F here this morning. On a brisk 12 mile drive at 65 mph my gauge shows right below the red portion but not touching. Upper radiator registered 185F and lower exit 155F so a 30F drop. I have a thermometer that fits into the oil dip stick hole at the same length and the oil registered 225F. All this looks ok but I do not like the gauge riding so close to the red portion. I have adjusted the tiny screws in the back of the gauge as well as possible.
[/QUOTE]
I missed this part. If the gas gauge is also showing high readings, the problem is the IVR. If not, it's the new sender. I'm not sure how you're reading temperature at the radiator, but those sound fine. If you like, I can send you a plastic thermometer than adheres to the thermostat housing for a precise reading. If the temps are verified and the gas gauge isn't reading high, then the problem is the new sender. The gauges in these cars are linear: the needle will deflect in direct proportion to current. But the temp senders are non-linear thermistors. Their resistance drops more slowly as temperature rises. Even with the best match, the temp gauge will be somewhat bogus. The gauge is calibrated to give a midpoint reading when the temperature is 185, but this assumes an original sender.. The problem is that modern thermistors don't match the classical Smiths sender curve precisely. You can spend a lot of money in a frustrating hunt for a sender than gives more pleasing readings. But lately, I've been suggesting recalibration when this problem happens. As long as the gauge is in good shape, it's very easy. Here's how.
Flip down the center panel and examine the back of the temp gauge. You will observe two tiny corks, these cover the adjustment cams. As you sit in the car, the one on the left changes the zero point, the one on the right the range. Poke out the cork and the adjuster will be revealed. Bear in mind that you'll be moving a cam, not turning a screw. These photos should be self-explanatory:
Just to make sure I am looking at this correctly.... the light bulb is at the bottom of the gauge, so when the door is down, would these two corks be reversed?
I've never tried any of this type of adjustment, if it's not a screw, then what is used to move the cams?
If you look at the second photo, you'll see two triangular plates. They pivot at one end and follow an arc at the other. You're trying to nudge these right or left, so don't try to turn them like a screw. If you have the door folded down and you're facing the front of the car, the cork on your right will adjust the range.
I can only speak to my near 40 years with our 4.2L S1, and it had most to do with our location in desert Aussie country where summer temps were always 40C (104F) or higher. Our worst, in late 70s was a high of 51C (123F) so compare with a really hot day in outback Arizona.
Our most important upgrade (I regarded it as a fix for inadequate engineering) had nothing to do with the OEM fans . . . it was to have our OEM radiator recored. IIRC the OEM had a core of 5 small rows of waterways. By comparison, our new recore held 7 more generously sized rows. It measured some half inch thicker core but this was not recognisable unless physically measured. Even under the many hot miles across our sparsely populated outback highways, that E-Type never again overheated. It turned "always borderline" into "unrestrained enjoyment".
Cheers and best wishes,
Last edited by cat_as_trophy; Mar 19, 2026 at 07:32 AM.
Radiator Cooling Fan Questions…4.2 Lt. Series II
