Coolant Blowout

I wish I would have found this forum earlier. I have been lucky in my choices so far, but I have found some helpful advice here already and I've bookmarked it for further review later.

I have a 2005 DC and it's having an issue with coolant blowing out into the engine compartment, especially after long drives, more so if towing. This makes the entire operation smell like a urinal cake, so it's totally unacceptable.

During this most recent episode, the temperature gauge, which I watch like a hawk now, is not showing any rise whatsoever for the engine temperature while on these long drives. I have replaced the radiator 2x now, Denso brand. Radiator cap has been replaced too, so I'm sure it's fine as well. I've even replaced the fan clutch as in earlier instances, it had only happened when I had to stop on a hot day.

After the last trip, I checked the radiator and it has no coolant showing over the cooling ribs or whatever you call the guts in there. I added about 1/3 gallon of coolant directly into the radiator to bring up fluid over the top of the guts. Oddly enough, the overflow reservoir is still about half full and I thought the purpose of that was to pull in fluid when the radiator needed more?

I am just at a loss as to why this keeps happening after so many attempts to quash it. I've included pictures with the splatter pattern in case that's helpful in troubleshooting.

 

Did you completely burp the system from air with your heater on high when you changed the rad? The overflow container catches the excess coolant from the radiator. As the coolant heats up, it expands and needs to go somewhere. Hence the overflow. As the coolant is cooling down from the engine not running, a vacuum is formed and the rad draws coolant back from the overflow to keep itself full. Two things to check: be sure the hose and barbed fittings on the rad and overflow and not blocked. Also, check your rad cap. There are actually two seals inside of it and both have to function properly. Hopefully it’s a factory rad cap. They are cheap. If there’s any question if it’s bad or not, change it.

 

I missed the part about you already changing the rad cap. Is it a factory cap?

 

replace the thermostat; make sure the jiggle valve as close to the 12 o'clock position as possible.

 

Great point. Could be a bad stat. I see Toyota offers a two stage stat for a premium as well as the normal one.

 

I don't see how the thermostat wasn't replaced while OP replaced the rad. It boggles my brain.

 

Thanks for all the replies. Yeah, thermostat was changed awhile ago, so it's not factory, but not very old either. Done by a competent mechanic. And I should be clear, that's not me! I can change my own oil, but that's about the extent of it. Per the question of air bubbles, whenever I have changed or added substantial amounts of antifreeze, I use the kit that my son has which sits on top of the radiator and lets it 'burp' while you run the heater and such.

I guess it could still be a crappy cap. Kind of looks like that, too much pressure at high temps, fast driving. The gauges always are steady when it happens. The last time was an 8 hour drive down to Bend, Oregon, but on the way back home, didn't happen again, as far as I can tell, although I wasn't checking as I should have. I saw someone refer to Amazon as Scamazon the other day which made me laugh because I was an early adopter and it is quite handy and a time saver. Having said that, my son, who knows cars much better than me said that I should buy all my parts from RockAuto. I definitely do for brakes and shocks and O2 sensors and MAFs and stuff like that, but I probably bought the radiator cap at the Happiest Capitalist on Earth Store.

I think I will go ahead and pull out the overflow container and inspect more carefully for leaks or cracks near the inlet/outlet area. In the end, I could ask Craig down at the repair shop. I think he's honest and straightforward, but he might have a look under the hood and hazard a guess since I've spent a lot of money there recently for a timing belt work and fixing a transmission leak.

Ok, just checked, here are some dates of Amazon purchases and services performed professionally, involving the cooling system.

5/17/2019 - Purchased Denso221-0518 Radiator (replaces factory radiator which I "guessed" to be the problem)
6/12/2019 - Serviced. New thermostat and water inlet valve was replaced or repaired (evidently new radiator did not fix it!)
3/12/2020 - Serviced. Notes say "Oil cooler hose blowout", need to find the receipt
10/29/2020 - Serviced. Tested cooling system, new radiator cap
9/17/2022 - Purchased Toyota Radiator Cap - 16401-20353 (from Scamazon, but has Toyota logos all over it?)
9/27/2023 - Purchased Denso221-0518 Radiator (Denso was recommended, much cheaper as same thing at RockAuto)
10/17/2023 - Serviced. Timing belt, water pump, asked mechanic to install Amazon purchased radiator

After all of this it was smooth sailing for a while, lots of 300 mile drives into Eastern Washington during hot months. Then all the sudden it takes a dump on the way to Bend?

 

This looks like a similar leak on my SC400 a while back. My case ended up being the radiator, it had cracked at the top corner under the beauty plastic and would splatter very similar to your pattern. I don't trust Amazon, since it's becoming the old Ebay where stuff may get refurbished and being passed as new. I snagged a radiator from the local stealership at a fair price. I looked up your model and OEM rads are about $190 at a local stealership, order online and pick it up in person, better than Amazon, just my .02cents. On another note you may want to inspect your hoses and your reservoir. I would let your truck run at idle and turn on your heater full blast with the hood open and check if you see coolant seeping from anywhere.

Edit: For reference,

 

I hate to say it bud, but this is your problem. There's damn good reason why it was much cheaper. With the spatter pattern, looks to me like you've got a leak in your radiator. Buy once, cry once.

 

Pressure test that radiator cap (or try a new one).

They can intermittently fail and pushing coolant out of the reservoir.