Hi, my coolant reservoir cap (not radiator) cap was damaged, literally fall of f the car while driving and I can't find it. I can't seem to find a replacement anywhere that isn't near $60. I was looking at this, which says it is compatible but almost seems like its universal as it claims to support hundreds of different cars.. will this work?

https://www.ebay.com/itm/18527671320...mis&media=COPY

Also, does anyone know the size of the overflow hose that I will need? Its odd that there isn't many replacement parts for this when there is many for other cars that cost less than $10.

I apologize. I misunderstood your question. That is not a cooling reservoir cap. That is a radiator cap. If you want the cover to the coolant reservoir you should be looking at something like this:
https://www.ebay.com/itm/23330083716...Bk9SR-CM5MziYA

I do not know what year/model you have so I can't be more specific. That is an example of what I "think" you are looking for. Radiator caps are pressure relief valves essentially. If you get the wrong one, you can over pressurize your system and do all kinds of damage.

Sorry I forgot to clarify. I have a 2003, and that is the model I can't find anything for that isn't $50 which seems kind of ridiculous.

Update. The hose you want is listed as "BREATHER; FOR RADIATOR RESERVE TANK", Lexus P/N 9044512117.
The entire assembly including the cap is listed as "CAP, SUBASSEMBLY, RESERVE TANK" Lexus P/N 1640546080. I believe that this P/N is the entire assy including the reserve tank cap and hoses.
The ebay equivalent is this: https://www.ebay.com/itm/25305567268...Bk9SR9KRi83iYA
Your right though. The price is pretty ridicules.

Paul

Sorry. The full link will not post. I believe that it is in relation to a ? in the string. Weird. Search this:
LEXUS OEM FACTORY COOLANT RESERVOIR CAP 1998-2005 GS300
Price $38.89
Sounds like a lot until you think about how much gas it takes to run around and find OEM parts.
Paul

There is one thing about that P/N that bugs me though. I do not see the tube that hangs down inside the reservoir in the Lexus parts Drawings. Do you have a friend or anyone that you could take a quick look at?

paul

There is a used one for a few dollars less. Search:
1998-2005 Lexus GS300 2001-2005 IS300 OEM Coolant Reservoir Overflow Lid Cap
Price is $30.00

And I do not see a center tube on that one either.

Paul