Leaking coolant - suggestions

Hey guys,

So I have been leaking coolant ever since I changed the coolant about 6 months ago. Since then I have replaced the radiator cap, water pump, coolant, and thermostat (Had my mechanic do the water pump, thermostat and timing belt). My truck passed a pressure check for the coolant system but now after the trip to the mechanic it is at about 200 F around town (was at 190-195F) and I noticed it was again leaking coolant. Maybe I just need a new radiator but wanted to see if any of you have experienced this. (All parts were OEM and I went from red to red and used distilled water to clean out the system before the change). I appreciate any advice!
Jacob

 

If the cap is new and the gasket is intact, the top of your radiator might be cracking. When they get old, the plastic can get brittle and it's not uncommon for the top of the radiator to crack and leak sometimes dramatically.

 

Yeah that was kinda what I was thinking just would think that would cause the system to fail a pressure test. Also the coolant is not being pulled from the reservoir either. Always scared of the head gasket but no bubbles when running cold with the cap off and not oil in coolant/vise versa

 

I would try a new cap, unless you see a crack in that area

 

Hmm, even though it is already a new cap? (The old one was doing the same thing).

 

Yeah, I have a scan gauge and just replaced the water pump and thermostat and it seemed to increase the running temp (193–>200). I read somewhere that sometimes if the thermostat is installed incorrectly they won’t operate, but my mechanic is normally pretty good.

 

kind of unusual since all major cooling parts are replaced with OEM stuff, try getting it up to operating temp pull off the road pop the hood with engine running see if u can spot the leak

 

But it would get past 200 easy on the highway before so I can’t say that wasn’t a thing. But now it is 200 a lot faster

 

I’m almost positive it is out of the cap

 

Or at that radiator neck

 

true

 

try an OEM replacement those aftermarket STANT aren't as good

 

I got everything from the stealership

 

Yeah the leaking is one thing and it might be a seperate issue with running 10 degrees hotter. As the guy above posted, the thermostat in the V6, the 3.4 L, actually is supposed to be installed with the bubbler valve/jiggle valve at the 6 o'clock position, which is opposite of any other thermostats I've worked on and seen. We know through experience here in the forum that folks that run the jiggle valve in the 'traditionally correct' position, at 12 o'clock will run hotter. Many mechanics do not know this about this engine as its contrary to pretty much everything they're taught or have seen. But it is true. We've seen it plenty of times with guys here in the forum.

But the leak looks like the leak I had in upper tank. Microcrack that when engine is heated up and coolant is hot then crack expands and you can see the coolant. If Check for the crack in tank after it's cooled off and shrank back down you're left staring going wtf did that coolant come from. It's a common leak, the upper tank splitting or losing seal to core, with our tacos

 

Great advice, I may bring it back and have him flip it unless I can find time to change it myself. I will also likely replace the radiator for good measure. Got off the phone with the dealership and they told me they no longer sell radiators for our truck which is a bummer. Also by upper tank you mean upper tank within the radiator?

 

https://parts.camelbacktoyota.com/search?search_str=radiator

 

Guaranteed to run 5-8 degrees hotter if the stat is in the 12 o’clock position if you have the stock radiator

 

Yeah the plastic upper tank is what usually splits. The lower tank is also plastic and not as common of a problem area.
As these tacos were made in 'Murica, the OEM radiator was made and provided by Harrison. For replacement, folks have found the Denso aftermarket radiators to be acceptable, myself included. I think there is another brand of radiator that guys have had good luck with here as well. Checking to see if thermostat is correctly oriented could be an easy diagnostic step for you. Even with slight leaking the cooling system should be able to keep the engine cooled off enough

 

Did you end up replacing the radiator? I have a crack in mine and am wanting to replace with denso but most seem to be for the autos.

 

I didn’t, it ended up being the cap but I may replace it soon