Was driving along and suddenly low coolant light came on. Was able to get home with no issues.
Upon inspection, looks like the low coolant sensor popped out of header tank grommet, like a turkey being done. I pulled the rubber grommet, pretty sure it is original!
I have a new header tank sitting around that i can prepare. It did not come with any grommet. Any advice?
I’ve ordered part, C43221. As it probably should be exact size grommet. Glue it in with RTV? Archives make it sound like it works well as is, for 30 years. I guess i got lucky at 36 years.
Just put the new grommet in, no sealant. It will stay in fine. Physics says it won’t come out under pressure, unless the rubber is deteriorated like yours was.
Originally the fan temp switch in the front of the engine used a larger version of the same seal/grommet. Only went to a screw in sender after a few years.
Make sure you new tank has the same size hole as the original. I got a tank with the incorrect size. And had to cut a section out of my old one and have it soldered over the new one at a radiator shop.
Funny, in that my tank grommet started leaking a bit on Superblue last month. I easily found a new one and the sensor itself from the same vendor on Ebay, and I think the total cost for both was less than $10 + free shipping. However, keep in mind that Superblue is a face-lift 4.0, so that may not be applicable to your XJS. btw, the grommet on Superblue is a friction fit. Again, no idea on the 5.3 V-12s.
Thanks for the advice. I just checked, hole in new header tank is correct.
My new header tank is again painted steel, about all that’s out there, but hopefully should last a while with my regular coolant changes. When i first got car, this header tank had corrosion inside, i cleaned out well. Same with bypass. Expensive, but found a stainless steel bypass, happy with that.
Yeah, our cars are getting over 30 years. Rubber does not last that long. I’ve been replacing every rubber bit i can find as preventative maintenance. This grommet, i forgot about.
Wow, that is one ugly grommet. When I replaced my header tank, I felt a bit nervous about the rubber grommet staying in place, so I put a long zip-tie, maybe two, clear around tank holding grommet in place. Everything is still where it should be.
Discussion some years ago on this list between Ed Sowell and myself about what keeps these rubber plugs from falling out or being ejected under pressure. Might be worth searching for if you are curious.
Don’t know about the pre-face lifts, but this new one I got - inserting the new sender probe inside the new grommet required a bit of “spit” + forceful pressure. Very close tolerance. I’m curious to see how tight it is when I go to insert the grommet assembly into the tank hole - may have to use something like WD-40 on it.
Reading thru archives, I’m confident to just install new grommet and sensor as is dry. But I think it’s wise as preventative maintenance to replace again when coolant hoses are replaced. (I usually replace coolant hoses every 10- 12 years as preventative maintenance.)
I am also replacing my expansion tank. Original has flaking paint and signs of corrosion inside. SNG makes them, perfect fit.
I am also replacing the sensor. 36 years, any wear on it will make the grommet not hold as tight. Even stainless steel wears away.
New one is 4.86mm. Old one is 4.65mm.
Fyi, grommet went in with minor force. Then sensor went in with maximum finger strength. That thing ain’t popping out anytime soon.
However, keep in mind that Superblue is a face-lift 4.0, so that may not be applicable to your XJS. btw, the grommet on Superblue is a friction fit. Again, no idea on the 5.3 V-12s.