Coolant everywhere…..cheapo radiator cap?

Short back story. About 2 years ago I did the timing belt, water pump, all new belts, all new hoses and a new radiator. I used denso everything….except the radiator cap apparently. Not sure why, I don’t remember. Also installed an extra large transmission cooler. Everything has been working great.

Saturday I was towing my travel trailer home. Fully loaded pretty heavy. It was like 105. Towed across the Sacramento valley mostly flat for like 1.5 hours. 4th gear, torque converter locked running about 208-210 coolant and about 180 trans pan. Stopped for lunch, let it idle for about 5 minutes to cool and popped the hood. All looked good. Then started pulling the hill up to Auburn. Knew it was hot so I slowed down. Pulled about 50-55 (could have gone faster but it was hot so no rush) the worst couple hills I was in 3rd gear for a bit. Coolant hit 222 and trans got to 200 but only briefly and then immediately dropped at the crest of each hill. I was actually pretty impressed for how hot and heavy I was with a/c blowing cold.

Got home and parked the truck. Let it idle to cool and popped the hood and saw the coolant everywhere. At this point it was pretty much dried. No sign of any active leak. Coolant was down to 194 and dropping. Coolant reservoir was basically empty (a little at the bottom)Shut it off and let it cool for several hours and popped open the radiator. Luckily it was full. Hosed everything down and then fired up next day. No leaks anywhere that I can see. Comes right up to 185 and stabilizes. There appears to be some coolant leaking around the top of the radiator cap.

I’m thinking the cap failed. Lost some or all pressure and the coolant boiled and blew out the overflow. Already ordered a genuine Toyota radiator cap. Anyone have any other thoughts?

 

Your thoughts are plausible and OEM remedy is spot on.

As for cap, appears to be a Murray 13 psi cap that one can get at AutoZone, O'reilly, etc....

Murray 13 psi Radiator cap 7736 | O'Reilly Auto Parts (oreillyauto.com)

In your case if indeed a 13 psi cap = 39 deg plus normal approx 190 + 39 = 229.
You were definitely pushing it but should be remedied with proper cap.

 

Here’s what I ordered. Hopefully this is the fix.

 

Hate to be a downer but you never want to buy parts from Amazon these days. A lot are counterfeit.

I would get a new cap from your local Toyota dealership.

 

What about rock auto? Is that place still pretty trusted?

 

Yes Rock Auto is fine but they don't sell Toyota parts. If they have a Denso or Aisin radiator cap that should be a fine substitute.

 

Ya I just saw that. The one off Amazon already shipped so I will see what it looks like. I’m not a fan of my local dealer. Can’t look up anything online. Have to call them to see if they have anything. and even then they usually have to order even the most basic stuff.

 

You can go to autozone and rent the radiator cap pressure test tool. Look between the fan to see if there is any coolant drooling.

my radiator failed last week because of a failed thermostat (it got stuck open and closed). It blew the the top of the radiator.

https://www.tundras.com/threads/radiator-replacement-double-cab-2006.127189/#post-3253882

 

I ain't gonna say your cap doesn't need replacing but I bet your puke bottle puked, hit your fan and that's what you're looking at.

 

Pay careful attention to the packaging. I mean, stickers are easy to fake, but most legitimate dealerships will use a specific type of sticker. If your package doesn't have this, you know the shit ain't real. Be suspicious if it says MADE IN CHINA. (Note: Some OEM Toyota parts are made in China! They have a lettering system to designate which parts are made where; counterfeiters usually get that wrong also, though)

​

 

The more I look at thia the more I'm leaning towards a cracked radiator. Otherwise there would be residue below that cap. The actual pressure may be opening that crack

 

BTW my SC400 got similar facials after I replaced my radiator cap.

Edit. I had just cleaned my engine bay to find the leak, I think I have a similar cap as yours.

 

I am pretty sure it all came out the bottle. It’s kinda hard I guess to see in the pictures but if you look at the spray pattern on my battery it really looks like that’s where all the fluid came from. I looked all over the radiator and really didn’t see anything. It was all from the fan backwards. I do like the idea of pressure testing the whole system though. Might do that when I get a chance. I’ll post pics when the new cap comes. It’ll be a little bit though. Going to be out of town for 14 days. Thanks for all the info!

 

I'd start with a new OEM Radiator cap, followed by a coolant pressure test. I believe you may be able to "rent" a pressure test tool at your local autoparts retailer (O'Reillys comes to mind). If I remember correctly, the tundra radiator caps are rated to 12.7 psi.

 

Happened to me. I filled the bottle between the Max and Low lines twice just to see what it'd do and both times I ended up with coolant everywhere.

 

New cap came early. Looks legit to me….?

 

Looks legit to this Toyota parts guy.

 

I put the new cap on. Ran the truck up to temp twice and it all looked good. Each time it pulled in some coolant after cooling down and I had to top off. Then on the third test I put it in drive and held the rpm’s at about 1,000 to heat up the coolant and the trans fluid. Got it up to 200 coolant temp and 180 trans temp. No leaks. Coolant went from about 1/3 on the overflow to maybe 2/3. Then after it cooled returned back to where it was. No leaks or anything. So I will monitor but I think I’m good for now.