2017 Tacoma Coolant Leak

I have been trying to figure out this leak for awhile. It seems to only leak after driving for a little while. It does not seem to leak when idling or even revving and sometimes I make it to work without it leaking. Other times it will be spattered all over. Just wondering if anyone has any ideas. I do have a dye in it, the dyed coolant does not seem to cycle through to the overflow tank but the overflow tank does get sucked out as I've had to top it off several times (I use the pink Toyota premixed). Last week the cap seemed to be wet underneath and I have taken it on and off a couple times to inspect it (and top off the radiator )and have another OEM cap on order. I put a clamp on the overflow hose because it had actually come off at one point (months ago) but the radiator has never been run dry and always topped off. I replaced the water outlet valve a few years ago and at one point, a clamp had slipped off the barb creating a leak in that location but I slipped it back on and haven't had any leaks from that location since. The radiator and the hoses underneath all look fine and I ran my finger over every barbed connection to make see the clamps were secure. A coworker was going to pressure test it but he doesn't have the right adapter. I was just wondering if anyone has any ideas. I have a trip coming up and don't have time to take it into a shop very easily. Attached are some pictures in between washing it with water.

Also, maybe irrelevant information but a few months ago somebody ran a red light as I was turning left and hit my passenger front end. I just got it back from the shop a couple weeks ago but this coolant leak has been an ongoing thing since before that (had it back in October too). They didn't replace anything in the cooling system as it didn't get damaged. It was mainly body damage, headlight, steering shaft, steering rack and tie rods. The Toyota dealership did everything but body. Seems like they would have noticed it but then again, if they didn't drive it much to test it, the leak probably didn't show.

 

Rads can crack from small accidents. It definitely looks like the case.

 

From the looks of it possibly the cap is the issue the rubber seal looks pretty worn out .

 

I would try a new cap.
Can also rent a pressure test kit from parts store.

 

It could be that the cap is doing what is supposed to be doing, opening up at high pressures and relieving the pressure. This may be why you not finding a leak in the hose or radiator. You problem may lie with the thermostat not opening up very much. I would look there first.

 

Im going to throw this out there. I got a new radiator installed in a vehicle but the plastic casting for the overflow was blocked and i didnt know until it caused a head gasket issue on the vehicle. I will always make sure the overflow is clear.

Clean up the mess and rent/buy a pressure tester. New caps are cheap also.

 

Is that the original cap or aftermarket? It looks like it's leaking. There's a two-stage seal in there. Yes it's supposed to open and let pressure out but the pressure goes down the expansion hose into the plastic reservoir. It should never spit coolant externally out into the engine bay

Try a new cap, OEM preferably..

 

I finally got my new cap today and I installed it after work and I'll check it again when I get to work in the morning. As far as I know the cap is original and I only install OEM Toyota parts. The new cap is sealed in a Toyota bag. It looks identical to the old one except there are 4 lines on the innermost rubber seal on the original and not on the new one. The first picture is this morning after another cleanup. I did put another clamp on the tank side of the overflow just to see if that makes a difference. None of the dyed coolant is ever getting push back into the tank but it is sucking out just fine as the pink coolant in the tank slowly depletes. Fingers crossed and if it still leaks, I'll take it back to the body shop or have it pressure tested at auto parts.

As for the thermostat, if there was an issue with it wouldn't it either stay open or closed thus making the engine temp too hot or cold? Because I'm getting good temps. And I actually did replace the thermostat a couple years ago, I was getting the check engine light and I think one or two other lights and it was having a hard time heating up and I ran my OBD and it said bad thermostat, so I replaced the water inlet valve because it includes the thermostat. So that is all pretty recent.

 

Got the new cap put on last night and drove it to work and back without a single leak and I noticed just a little of the dyed coolant got pushed back into the overflow tank. So a bad cap was the problem and instead of the excess being pushed into the overflow, it was being pushed out the cap. So if anyone else has this problem, definitely replace the cap...

 

Thanks for following up with your solution, Evan. Hopefully this information will help others in the future. Righteous!