Sudden overheating, missing coolant

fish0281

fish0281

New member
For the sake of brevity:

Truck was running hot yesterday (not pegged, but on it's way) and I've never seen it run warm before.
I could also smell the coolant yesterday.
Checked coolant this am, radiator had no standing fluid, nor did the res.
Last topped off at the beginning of summer
Never see any puddles or messes under my truck
Never noticed any white smoke in the exhaust

Possible causes:
Head Gasket
cracked/warped head
cracked block
leaky radiator
engine block frost plug popped (recently had freezing weather)
leaking water pump (it's due for replacement)


Anyone else experienced something similar? Any other thoughts on possible causes?
 
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Possible Strawberry Milkshake? Pull the trans dipstick and see if it looks pink and foamy. Sometimes the radiator will leak fluid into the transmission thru the integrated trans cooler. If this is the case, you'll want to replace the radiator and flush the trans very well with all new fluid.
 
badattitude said:
Possible Strawberry Milkshake? Pull the trans dipstick and see if it looks pink and foamy. Sometimes the radiator will leak fluid into the transmission thru the integrated trans cooler. If this is the case, you'll want to replace the radiator and flush the trans very well with all new fluid.
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I'll double check, but I doubt it. I'm pretty sure if the transmission cooler leaked, it would be evident in the coolant that I could see when I checked, but good idea on another thing to look into.
 
Heater control valve

I had a leak out of the heater control valve that caused my 97 to lose coolant and started to overheat on me. Changed the control valve with one from Oreillys and it has been all good since then.
 
That Sucks man.

The coolant went somewhere though lol.


How many miles?

Have you done a compression test? Post the numbers.

Have you looked in the CYL by removing the spark plugs? The one that is clean and has less or no carbon is the one with coolant flowing into it.

Those are some cheap suggestions you can do at home.
 
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Sudden significant fluid loss from hoses/pipes. This might not produce noticeable steam and might only leak while in motion. The rear heater pipes (if so equipped) are especially apt to do this.

Visually inspect entire system after it has been running for a while and then perform coolant pressure test. I'd do the coolant pressure test before I did a compression test. Horses, not zebras.
 
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top it off with water, then run it and watch for a leak.

if its a bad leak, it will be obvious.
 
I wouldn't start thinking major problems like a cracked block, bad head gasket or warped head. It could be something as small as a bad gasket in your coolant system. Start small and work your way up until you find a leak/cause of the leak.

I would not see how your truck could burn all of the coolant without you noticing any smoke or running absolutely terrible burning that much coolant so fast (unless you haven't checked it since summer time?)

I would visually check and see if any freeze plugs popped out, then fill the radiator back up and look for a leak pretty much through your whole coolant system. Hoses, heater core valve, radiator cap, water pump leaking, thermostat housing leak, check for burning coolant though your exhaust ect.
 
Thank you everyone for the great advice. She has about 200k miles and I have been noticing a steady decline in fuel mileage, as well as power (but that's hard to judge when it didn't start with much).

I'll start with the obvious - look for clear signs of leaking. Then I'll probably do a coolant pressure test and compression test, and go from there. I am also due for timing belt et. al. and have a new radiator in waiting, but before I tear into that, I want to find out if I need to take care of any other major items (e.g., head gasket) so I could do it all at once.

Also, anyone have experience with those chemical tests to determine if there are exhaust products in the coolant? Would a cooling system pressure test trump that test?


On the bright side, it did pass emissions on Tuesday! :/
 
fish0281 said:
Also, anyone have experience with those chemical tests to determine if there are exhaust products in the coolant? Would a cooling system pressure test trump that test?
:/
Click to expand...

I have a cooling system hydrocarbon tester you'd be welcome to borrow. I'm in Fort Collins.

The coolant pressure test is better and more exact in my opinion. I like to remove the spark plugs and put the pressure tester on it for a few hours and check which cylinder is getting coolant in it. This way you are able to isolate down to the specific cylinder rather than just... "Yup hydrocarbons in the coolant"

PM me if you want to borrow anything over the weekend. I'd honestly run you down some gear to Denver Saturday morning if you can bring it back to me by Sunday evening (I don't work weekends)
 
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EatonKyleH said:
I have a cooling system hydrocarbon tester you'd be welcome to borrow. I'm in Fort Collins.

The coolant pressure test is better and more exact in my opinion. I like to remove the spark plugs and put the pressure tester on it for a few hours and check which cylinder is getting coolant in it. This way you are able to isolate down to the specific cylinder rather than just... "Yup hydrocarbons in the coolant"

PM me if you want to borrow anything over the weekend. I'd honestly run you down some gear to Denver Saturday morning if you can bring it back to me by Sunday evening (I don't work weekends)
Click to expand...

Thanks man, that's really nice of you! I can't get to it until next weekend cause I am out of town this weekend though...

Good point too, I think I'll go the pressure test route and see where that gets me.
 
5vzT4R said:
Exactly!!! She is way to young to be having these issues.. :D

But no, I personally have no experience with those test.
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Actually its perfectly plausible to have a cracked head or bad head gasket at 200k miles. Even on a babied vehicle.

It doesn't mean 4Runners are not reliable, quite the opposite actually. We tell members to change their Water Pump every 120k-ish miles and that is fine. What I am suggesting is that the MTBF for properly cared for heads on these trucks seems to fall somewhere between 175-225k. It doesn't mean that they will fail just that it wouldn't be a anomaly.


It happened to me, it has happened to a LOT of other on this forum between 175k-225k miles.

When I went in to the Toyota shop and talked to the Mechanic, someone who sees 50-100 4Runners or Tacoma's a month he told me it was "not unusual at all"

OP, check for leaks on ground. I hope you don't have any larger issues.
 
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BrianSD_42 said:
Actually its perfectly plausible to have a cracked head or bad head gasket at 200k miles. Even on a babied vehicle.

It doesn't mean 4Runners are not reliable, quite the opposite actually. We tell members to change their Water Pump every 120k-ish miles and that is fine. What I am suggesting is that the MBTF for properly cared for heads on these trucks seems to fall somewhere between 175-225k. It doesn't mean that they will fail just that it wouldn't be a anomaly.


It happened to me, it has happened to a LOT of other on this forum between 175k-225k miles.

When I went in to the Toyota shop and talked to the Mechanic, someone who sees 50-100 4Runners or Tacoma's a month he told me it was "not unusual at all"

OP, check for leaks on ground. I hope you don't have any larger issues.
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I'm curious as to what MBTF means.. I googled
it with no answer. Lol.
 
It cracks me up how quickly everyone jumps to the catastrophic possibilities right away.

OP, how does it run? Any sputtering or hesitation? A bad head or head gasket is pretty obvious when its running. It'll fall on its face? How does it shift? Pink milkshake would have the trans slipping. A leaking water pump wood leave puddles where you park.

How's the under carriage? Any rust? Most likely you're dealing with the very common leaking rear heater lines. Simple fix. Cut them out, replace with 3/8" rubber lines and you're good to go. When these leak, they do so gradually. They don't hold a lot of volume so you tend not to notice the leak. I don't believe (but could be wrong) that they're pressurized after you shit the truck off either. So they kind of tend to weep slowly rather than dump a lot at one time.

Look there and then post back.
 
I really haven't had much time to do anything other than peer in from the hood and look in through the wheel wells, but I see absolutely no signs of leaking. The coolant that is in the system is not pink milkshake, nor is the transmission fluid. Engine oil from the dipstick looks good (even though I'm over on my change... *sigh*).

I'll keep you all updated on what I find out as I get there!
 
PitbullRescuer said:
It cracks me up how quickly everyone jumps to the catastrophic possibilities right away.

OP, how does it run? Any sputtering or hesitation? A bad head or head gasket is pretty obvious when its running. It'll fall on its face? How does it shift? Pink milkshake would have the trans slipping. A leaking water pump wood leave puddles where you park.

How's the under carriage? Any rust? Most likely you're dealing with the very common leaking rear heater lines. Simple fix. Cut them out, replace with 3/8" rubber lines and you're good to go. When these leak, they do so gradually. They don't hold a lot of volume so you tend not to notice the leak. I don't believe (but could be wrong) that they're pressurized after you shit the truck off either. So they kind of tend to weep slowly rather than dump a lot at one time.

Look there and then post back.
Click to expand...

I agree, it's not always the best to jump to major-issue conclusions, but major issues aren't always super obvious either. It doesn't sputter or fall on it's face. That being said, there are no obvious signs of leaking... and it's gotta go somewhere.

The undercarriage of my truck is pretty much rust-free. Thank you Oregon for keeping your roads salt free. I didn't look at the rear heater lines, but I suspect they're fine.
 
PitbullRescuer said:
It cracks me up how quickly everyone jumps to the catastrophic possibilities right away.

OP, how does it run? Any sputtering or hesitation? A bad head or head gasket is pretty obvious when its running. It'll fall on its face? How does it shift? Pink milkshake would have the trans slipping. A leaking water pump wood leave puddles where you park.

How's the under carriage? Any rust? Most likely you're dealing with the very common leaking rear heater lines. Simple fix. Cut them out, replace with 3/8" rubber lines and you're good to go. When these leak, they do so gradually. They don't hold a lot of volume so you tend not to notice the leak. I don't believe (but could be wrong) that they're pressurized after you shit the truck off either. So they kind of tend to weep slowly rather than dump a lot at one time.

Look there and then post back.
Click to expand...

I'm with you on this one. I had a similar situation on my rig, low on coolant and the temp needle moved some. I can't even remember the last time I checked my coolant before this and the motor runs fine, zero issues. Leaking rear heater lines, leaked slow enough I didn't notice whatsoever

Very well could be a water pump with a slow leak as well
 
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