Pink coolant leak

Hey everyone. I need some advice. After a 30 min drive in 92 degree weather, I stopped for a haircut. I waited in my truck until I was called in. I had the truck and AC on.

After 20 minutes, I walked to the front of the truck, and noticed pink coolant leaking from the engine bay. I opened the hood and noticed the coolant reservoir was filled to the top and was leaking from the cap vent slot. l checked hoses for cracks, but didn't see any.

After the haircut, I reinspected. The coolant in the reservoir had adjusted itself, and was almost near the low level line. I turned the truck on. I didn’t see any leaks, and the temp gauge marked normal. I drove it home with the AC on.

No codes appeared.

I'll add coolant later, but I was curious if anyone could chime in and give me some possible reasons for the leak.

FYI: not a lot of coolant was lost. The water pump was installed not long ago. This is the first time its leaked coolant.

Any input is appreciated.

 

Here's my educated guess...

While you were parked, the truck started to overheat (probably not damaging), but the coolant was expanding with this increase in heat.
The extra volume created in the coolant system expands into the overflow tank (where you see the F & L lines) and then more pressure built up and coolant was coming out of the overflow hose on the overflow reservoir.

You went to your haircut and the truck cooled down.

While the truck cooled down, the decrease in coolant temperature also decreased the volume, so it created a vacuum in the system which drew coolant from the overflow reservoir back into the engine/hoses, which you then saw as a reduction of fluid now at the L line.

You are likely fine, but I don't recommend letting your truck run at idle with the AC blasting if you're not moving for a while or you may overheat your engine, crack your heads, cause head gasket issues, et al.

Top it off and watch the fluid level over the next few weeks. If it's consistently dropping now, you have overheated your engine.

 

Copy. Thanks.

 

Jason hit it spot on! Take his advice on hot days and parked with no air flow,
I’m retired FF 21 years. Seen an ambulance go up in flames doing that

 

Something created pressure in the cooling system.
I’d probably have someone do a coolant system pressure test.
I haven’t seen any of these trucks “overheat” without the temp gauge showing well above normal.

With 320k, I’d do a coolant system pressure test.
Followed by an exhaust gas analysis of the coolant.

Most importantly, I’d monitor the coolant level closely.
Don’t just check the reservoir, check the radiator as well. (Make sure the engine is cool)

 

Something is awry with your cooling system.

I blast my AC while idling for hours in 100+ temps with zero issues.

 

Thanks all. I'll take a look at the radiator fluid level later tonight.

I've been reading several threads about this issue, and some mention head gasket issues. I hope that isn't my issue.

 

Bubbling reservoir is a symptom of a head gasket, sorry to say. Get the tests done, hope for the best.

 

Bubbling coolant is not just expansion. Get a combustion gas test done.

 

If the water pump was just replaced, the bubbles you saw may have been an air pocket getting purged

Or it might be a headgasket, but that is usually indicated by a slow loss of coolant over time

Try a chemical block test.. or just simply monitor it and see if it happens again.

Keep an eye on the coolant level over the next few weeks. If it steadily keeps going down and bubbling from time to time, headgasket is suspect.

If the coolant level is always the same and it still bubbles, look at the temp and see if its spiking up above normal. Check fan clutch and thermostat. Does the new water pump have a plastic impeller? Is it spinning?

 

2007 Tacoma O.P. you should be okay as far as the headgasket,as long as the truck didnt do a major overheat.

 

@b_r_o: not sure if it has a plastic impeller.

I'll drop it off at the dealer, as most of these tests are beyond me.

Since they can't fit me into their schedule until next week, I'll monitor the coolant levels daily.

 

If nothing happens in a week,I would not bother going too the dealer.

 

This has happened to me before , not as bad as you but when the coolant gets pass the cap or should I say when the rad cap let's coolant out it is pressurized and makes a mess . I also have pink crust around the little hoses on the overflow tank.
Wonder if the rad cap is weak ?

 

Did you happen to notice what the temp gauge said while you were parked waiting? You dont mention it in the first post.

An easy thing, relatively speaking, to try one afternoon is to flush / wash the radiator with a garden hose sprayer. Its amazing how much crap and dust can accumulate in some cases. Ideally you would pop the fan and fan shroud off and flush from the back side. But you should be able to get a lot of it from the front as well.

 

More correctly, something created excess pressure in the cooling system. Once it heats up, it's always runs under pressure.

 

@SR-71A: the temp gauge never went past half, which is weird. If the truck overheats, shouldn’t the gauge needle be in the high zone?

 

Like steelcity mentioned.. you might try a new rad cap. if its weak it will let too much coolant into the reservoir

 

Correct, Between 13 and 16 psi.
Depending on the cap. TRD cap is 16 psi for some odd reason? I believe stock is 13 psi.

 

OP here. Update from the dealer: They did a pressure test on the radiator and the cap. The cap didn’t pass. The seal within the cap had disintegrated. No leaks otherwise.

Total cost was an hour of the dealer’s labor plus the cost of the OEM new cap ($22).

Thanks everyone. Hopefully this will do the trick.