Need help with coolant leak from reservoir

Hey guys on my 21 Limited while doing some under hood cleaning a week or so ago I noticed that the reservoir coolant tank had dried coolant stains on the sides of it and on its lid> Looked like it most have over flowed at some point and spilled out abit. Truck otherwise seems to drive fine, but it is pretty cold here. I cleaned it up and added coolant to the reservoir so its in the normal filled range. Do you think this could be a bad radiator cap causing overflow to the reservoir tank? Not sure what other than that. Any ideas? Wife was driving it and has no idea when it leaked.

 

Take the overflow cap off, flip the gasket inside the lid around. Put it back and monitor. The gaskets lose their sealing ability and start to spill a little. I flipped mine and have not noticed anymore. You can also buy a new cap but the gasket is the only thing worn.

 

^ second this. My 24 sometimes has the pink crusties at the top of the tank, not much but some. Lately it hasn’t, but we’ve had cooler weather down here in South Florida.
If you notice it doesn’t take much to take that black plastic lid off, so seepage is easy to come out but flip it over and wipe it off good and reuse like rocko said

 

Guys you use anything to clean the rad cap gasket? Or just wipe with rag and flip it over? Thanks for the help on this.

 

Rag or paper towel. If the flipped gasket doesn't seal, some make a new gasket out of rubber tire inner tubes from a bike.

 

Thanks Rocko ill give it a try this weekend. Appreciate the help

 

No problem.

 

Or you can just replace the radiator cap with a new one. They are cheap enough:



Motorad T37

The other possible explanation is you have a head gasket leak, which would be extremely rare for a 5 year-old 5th gen.

 

Yeah i see the stealer has them for about $40 bucks. Thanks guys

 

just to clarify, flipping the puke tank gasket? or is there one on the radiator cap that you're referring to?

 

Its the rad cap. The overflow is just plastic snap on cap with no gasket but has an overflow 90 spigot where it dumps out of.

 

Overflow tank cap gasket. It does have a gasket in the lid. Thin, but it's there. If yours gone, there is the issue.

 

for the rad I did some reading and some say use a higher boiling point rad cap? Should I get a higher rated cap, if so what brand is safe? Or just get stock one? Ill check overflow to see if gasket still there.

 

^For a stock cooling system, use cap with stock opening pressure (1.1 bar or 16 psi). Doesn't have to be Toyota cap, but keep stock opening pressure. Otherwise you can blow a hose before the cap opens to the overflow tank.

The suspicion is your current cap is faulty (bad seal, bad spring, whatever the cause may be) so coolant is reaching the overflow tank before the cap's rated pressure is reached.

 

The stock radiator cap is perfectly fine. Anything else is a waste of money. It is a maintenance item though and should be changed if the seal looks damaged.

 

Never get higher pressure/temp radiator cap in a stock setup. Only use OEM stock.

 

alright that answers that..stock it is. Thanks guys

 

I think the recommendation to flip the gasket, or to cut a new one out using other material, was referring to the plastic flip cap on the radiator overflow tank where you say you’re seeing the pink crust.

If you don’t see pink crust on you actual radiator cap on the radiator, I don’t think replacing that gasket is going to help.

I’ve had pink crusties on my plastic overflow tank cap since it was new. I though maybe it was the plastic flashing on the mouth of the tank. Tried to knock down the flashing, but the crusties return. I might try to check on the plastic cap gasket to see if I can get it to stop…eventually. It’s been 80k miles, so I guess I havent been in a hurry about it.

 

It is a psi thing like you said, raising the psi only gets you a few degrees higher boiling point, and apparently "stock" worked when new. Great advice.

 

https://parts.elmhursttoyota.com/oe...ap-n-type-with-trd-logo-18-5-psi-ptr040000003

 

The OP has dripage on the overflow tank near the lid as I did. This is common and it's the gasket failing. I solved this by flipping the gasket, on the overflow tank cap. You can also buy a new cap if so desired. Part 16405-50051.

 

Geez. Paid $3.00 for one on RockAuto.

 

Does yours have the TRD sticker on it...

 

No, it doesn't. But for $3 I can't complain. Not like I look at it everyday anyway, lol. I also have a 2nd gen, so no TRD stuff anyway.

 

That is for a TRD cap @ $42, you're paying an extra $24 for the "TRD" label over what a normal cap will cost you...can be had for around $18.

That being said, they say that TRD label will increase your HP and mileage by about 10% to 15% , your mileage may vary!!

 

Slightly off topic but I changed my radiator cap at 70,000 miles when I did the trucks first coolant change. No reason other than I had read it to be a maintenance item somewhere. Prior to that I cleaned out the AC condenser and radiator with a long reach air wand and water wand. There was a lot of dirt/debris trapped between them. With that said after all was done I had a few long trips in the truck down to North Carolina in August and also some higher terrain with long uphill pulls. The truck actually ran a few degrees cooler than I could recall from similar trips in past years.

 

1.1bar stock cap to 1.3bar TRD cap --> benifits

 

There maybe some benefits, but they aren't really needed the stock cap works just fine.

 

Related question, has anyone cut a hole in the plastic cover to allow access to the radiator cap without having to remove all the clips and cover? I'm getting ready to change out coolant and was thinking about doing this. The outline for a relief cut seems to be pretty obvious and I can't think of a downside.

 

I wouldnt the plastic cover acts as some sort of air laminizer to aid cooling of parts behind it. If you chop it you may disrupt the incoming airflow and have cooling issues. Get some new christmas trees if the old ones are shit.