Sourcing a silicone heat sink grease for engine block heater (Kats cartridge heater)

Yes, I was looking at this same grease too, since it is a heat sink type and some customer reviews mentioned that they used it for their engine block cartridge heater install.

 

Today I have installed the heater with Permatex Silicone Dielectric grease that I already had on hand. I installed it from the above. Will see if there will be any issues with performance.

At the end I've accidentally dropped 12mm long socket after torquing that specific high voltage cable bracket located in front of the heater from installation instructions and cannot find this socket, even after taking off the whole underpan cover. I looked high and low with flashlight and fished with magnet and reached everywhere I can reach by hand. Not sure what else I can do, maybe I'll run a compressor tomorrow morning and blow air everywhere I can reach in hope that the socket will move, make some sound and reveal itself somehow. Anybody has more advice on that?

 

Compressed air blown everywhere I could reach did not help to reveal the dropped socket. Decided to take the driver side front wheel tomorrow to see if I can get more access to the area of interest. It will be quick to do since the car is already lifted and secured on jack stands.

 

After taking front left wheel off, the dropped 12mm socket was located hiding in a small nook under the steering assembly support.
All parts assembled back and checked, and back on the road again .

I think this KATS heater should be holding OK. The clip that holds it to the engine block sprang two times from me disappearing into the darkness of the engine bay, but then was quickly found on top of oil change opening underpan cover.

And that is the happy ending of this aftermarket heater install story.

 

My car is also living in a winter salty and rusty belt of South Ontario. I cleaned the heater placement hole with a short pipe brush before install as much as I could reach and the hole as I measured by a small stick seems to be a little deeper than this heater. The installation requires quite a bit of patience for first getting the obstacles like cowl and cable brackets out of the way and then persuasion of the heater in the hole while greased and air bubble behind it does not want to be squeezed out quickly acting like an air spring and bouncing back, but with persuasion, rotation and constant pressure it eventually gave up and settled in place. I guess if one is a left handed then pushing the heater could be easier, since I could only do this with left hand from the top. And then the spring clip can be installed to hold it in place.
Important to note that this job can not be rushed, otherwise the spring clip and wrench sockets get lost in the engine bay with much more effort to find them than the install itself. I had to lift the car and go under when dropped the retaining spring and then the socket. I tried to reach the hole from the bottom, and for me personally, I do not think I could reach that far to push the heater hard enough.

Couple tips how not to drop bolts and sockets:
1. Use magnetic sockets if you have them, or use the tape trick (credits to YT'ber Car Care Nut) to fix the HV harness bolt to the socket while placing them back so they do not drop. I personally used a small duct tape strip, it held the bolt on the socket exceptionally well.
2. When lifting the socket with extension and wrench from a tightened bolt, not just pull it up, but rather rock back and forth to fully free the socket from a bolt first so it does not disconnect from extension and drops down the engine bay.

After doing wipers and cowl removal a few times now, I find it quite easy and relatively quick so it is not a big deal anymore. I am using a cordless impact driver for those many 10mm bolts, similar to YT videos. I do not disconnect harness from the wiper motor assembly and just put that on the side of the car with it resting against the right front tire to save time.

Just sharing my experience here.

 

This is a relatively small cartridge heater and at its 400W capacity it would only increase the engine block temperature by 25C or so to have a smoother start and help the engine heating faster to a working temperature, that is all. The cabin heater will only start working (Auto mode) when the engine is fully warmed up. It is NOT recommended to start heater manually when the engine is cold as it will increase cold engine working time, which is turn causes more wear on the engine. If you need to warm Prius cabin before you run the engine then another method needs be researched for that. Apparently Prius has an electric heat pump tech in it for climate control, which one of the several reasons why I like this car, it does not need run ICE to maintain heat or cool. The electric pump works down to 15F(-9C) and then engine heat is needed to warm the cabin. I found this thread on this cold climate heating topic in the forum.

 

100% agree with how it would be a royal pain reaching from underneath. I wondered how difficult it would be after I lifted the car and removed the underpanel to find the dropped socket. Lifting Prius to a workable height is an operation by itself: I run it on the ramps first then use high lift floor jack and install 6t jack stands to get a good clearance access. I do not trust my life to those short 3t jacks.

It was not hard for me to reach from the top once I located the hole (light and mirror helped), but it is mostly the left hand only operation with sometime the right hand helping to manage HV harness hardware. I could do it again if needed from the top, no problem. Less work, cleaner and more safe.

 

Mendel,
You can be right about when heat pump tech was introduced in Prius. I only know that AC system in my generation Prius is fully electric, not a belt driven like in traditional cars. This means that Prius will maintain the temperature inside with ICE needed to run only periodically to either replenish the HV battery or engine coolant heat. And that is a really nice feature and great design.

I did not have the cowl off before installing the heater, I've taken it off for that purpose and it was easy once I have done that third time now: first to change spark plugs and second time to clean EGR. I guess it is the same repeating operation as you do with the car lifting and underpanel removal: the more times you do it the more comfortable you get with doing it.

 

I can take the cowl off in 5 min. Here is a YT video on that.

 

You are correct, it is cooling only if there is no heat pump technology yet.

 

Thanks for useful information Mendel, really appreciate that. I have now plugged in the heater and wondering how much time is optimal to plug in advance for optimal engine temperature? Thinking of a timer to plug in at evening before next day driving....