I think that there is something wrong w/ my coolant...

[shotgun_willie]

A couple of weeks ago, I purchased a new to me but definitely well used '97 5-speed, 4wd, SR5, 4runner w/ 216,000 on the clock. It is a "mom's" car. Lot's of miles, not really abused but w/ an interior that has seen several children come and go and a service history that is questionable at best. The truck runs just fine but I'm trying to make up for years of neglected maintenance before something inevitably goes wrong.

I took a look at the coolant in the reservoir and it looked kind of brown and rust colored. Last night I went about trying to flush the coolant. I ran about 6 gallons of water through the radiator before it was coming out mostly clear and then I went about filling the radiator and bringing the engine up to temp to clean out was was left in the engine block.

Here is a picture of what the coolant looked like....

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I'm not sure exactly when in the process this picture was taken but after running 8 gallons of distilled water through the engine, it hadn't changed much. As 3:00 AM approached I topped everything off w/ Toyota coolant and called it a night. My question is where do y'all think that I should go next? Is this just dirtier or is this a symptom of a larger problem that needs to be dealt with?

Thanks in advance any help. I did search on the forum a bit before posting but most people suggested to flush the coolant, but since I already did that I figured I would post and see if y'all could help me determine what my next move should be.

 

[kolelt]

It looks like strawberry milkshake issue. But correct me if I'm wrong, the manuals are immune to this problem ?

Check your tranny oil

Mayne replace radiator !

 

[02SE]

If the water coming out was still looking like that, when you stopped and filled it with coolant, I'd suggest draining the coolant again and flushing it with an actual radiator flush chemical while following the directions on the bottle. Then flushing that out with distilled water until it runs clean. Then install new coolant/water mix.

Keep in mind that with that much corrosion going on for who knows how long, it might be only a matter of time until problems such as leaking headgaskets arise.

 

[02SE]

It looks like strawberry milkshake issue. But correct me if I'm wrong, the manuals are immune to this problem ?

It's not the "strawberry milkshake" issue which automatic trans vehicles can have.

The 5-speed manual does not route it's gear oil through a heat exchanger in the radiator.

The pictures are just evidence of rust from the cooling system being seriously neglected for far too long.

 

[TheDurk]

No chance of milkshake with a 5-speed. If the before was truly nasty, 8 gallons is not enough to flush out especially if you are not using the block-drain when letting out the coolant. That just looks like a mix of rust/crud and coolant. Buy another 8 gallons of dH2O and flush a few times using the block drain

[Open bolt at blue arrow and coolant runs out tube at red arrow.]

as well as rad drain. Run 30 min or so between fills. Do first one with a flush cleaner. I won't use them on a well-maintained cooling system, but I fear you don't qualify. Get the H2O nice and clear before you fill with new Toyota Red and dH2O.

 

[amalik]

It's not the "strawberry milkshake" issue which automatic trans vehicles can have.

The 5-speed manual does not route it's gear oil through a heat exchanger in the radiator.

The pictures are just evidence of rust from the cooling system being seriously neglected for far too long.

Is the 5speed fluid cooled through an integrated cooler or what?

 

[TheDurk]

Is the 5speed fluid cooled through an integrated cooler or what?

No external cooling. None needed.

 

[shotgun_willie]

thanks for the help y'all. Happy to hear that I don't really have to worry about the pink milkshake issue. A little bit nervous about what this means for my engine long term though. Gonna go ahead and flush it again, using the block drain per The Durk's advice. I'll keep y'all posted w/ the results.

One other quick question though. Is coolant this bad a symptom of a larger issue, or just bad maintenance? Is there anything else that I should be doing to ward off headgasket issues? As a former Subaru owner, I'm always worried about the headgaskets and I want to avoid that repair if at all possible.

 

[JBurt]

You could do a compression or leak down test to see the current ability of your engine to hold pressure. If it is good I would just do as much maintenance as needed and have a hell of a lot of fun with your rig.

Congrats on the new rig (and 5-speed!) btw.

 

[TheDurk]

thanks for the help y'all. Happy to hear that I don't really have to worry about the pink milkshake issue. A little bit nervous about what this means for my engine long term though. Gonna go ahead and flush it again, using the block drain per The Durk's advice. I'll keep y'all posted w/ the results.

One other quick question though. Is coolant this bad a symptom of a larger issue, or just bad maintenance? Is there anything else that I should be doing to ward off headgasket issues? As a former Subaru owner, I'm always worried about the headgaskets and I want to avoid that repair if at all possible.

It indicates your coolant was operating past the effective life of the anti-corrosion additive package. This means crud was building up in your radiator, engine water jacket, and heater core (cores if you have rear heat). If you're lucky, most of it will be removed by the flushing process and coolant flow has not been compromised at any point. You can figure expected life of your water pump has been reduced.

I would recommend a Scanguage or other device for full-time monitoring of engine temps for your future peace-of-mind and do your next coolant change at 25-30K and see how things look. You could be just fine. If temps climb under load on hot days, your rad may be clogged and a new one might resolve that. Do what you're doing and see how it goes.

The headgaskets become compromised when the engine overheats, not because of aged coolant. So far, there is no reason to think this has happened.

 

[nevada]

I wouldn't be too alarmed, assuming its still running/working well. I see this type of thing OFTEN.
in fact, ive done 3 cooling system flushes in as many weeks, the most recent being on Monday.

its just a matter of neglect, and poor maintenance.

 

[02SE]

The headgaskets become compromised when the engine overheats, not because of aged coolant.

An engine overheating, is almost always due to poor or a complete lack of maintenance.

Exceptions would be using a vehicle that is in otherwise good condition and well maintained, far beyond it's design limit. Like towing far more than the vehicle is rated for. Or driving through a mud bog, and caking the radiator with mud.

Neglected coolant that becomes acidic, starts to erode the the cooling system internally. Including the coolant passageways in the headgasket(s). Eventually the erosion can become bad enough that leaks start, even if the engine has never overheated.

I've seen it numerous times over the years when I worked on consumer cars for a living, and since then when helping out friends or family.

 

[TheDurk]

The causes of overheating are many, only some of which are always due to poor maintenance. Coolant loss due to hose failure, fan clutch failure, thermostat failure, water pump failure, restricted coolant flow due to corrosion in water jacket or radiator, improper head-bolt torque, just to name a few. My own experience and every article I have seen points to overheating as the major cause of headgasket failure, with improper installation being second. Most blown HG's show the initial fail at the fire ring, which is not in contact with the coolant.

While acidic coolant can degrade HG's, the greater concern is the acidic coolant's effect on the aluminum head and radiator leading to flow restriction and overheating. This can be fatal not just to the HG but the head itself. My point to the OP was that there is no evidence than anything like this has occurred due to the aging coolant in his engine. If damage to the HG due to acidic coolant has occurred, there is really no way to know about it until the HG actually fails. In any case, the coolant is only in contact with the edges of the HG, while it is in contact with the entire interior surface of the radiator and water jacket.

That said, I respect your hands-on experience with failed HG's. No machine I maintain has ever lost a headgasket. I take coolant and cooling system maintenance seriously.

 

[02SE]

The causes of overheating are many, only some of which are always due to poor maintenance. Coolant loss due to hose failure, fan clutch failure, thermostat failure, water pump failure, restricted coolant flow due to corrosion in water jacket or radiator, improper head-bolt torque, just to name a few.

I would include all of your listed examples under poor or lack of maintenance (or simply incorrect, such as improper head-bolt torque). I just didn't spell out every possible scenario.

That said, I respect your hands-on experience with failed HG's. No machine I maintain has ever lost a headgasket. I take coolant and cooling system maintenance seriously.

Keep up the good work. It's appalling how most people treat their vehicles. I'm glad I no longer have to make a living fixing their negligence. Although I guess there wouldn't be as much need for qualified Mechanics, if people took better care of their cars.

 

[BlackWorksInc]

It reminds me of spoiled Dexcool (which unfortunately some people erroneously put in their vehicles)

I would like to point out that type of nasty corrosion can also occur from the wrong coolant being used for protracted periods of time.The differences in additive packages can cause the coolant to break down prematurely and/or cause damage.

One more thing for the OP, did you remove the thermostat when you flushed your system? I would pop the thermostat off and run some more water through it and see if that helps, if you're trying to flush the system with the thermostat in, it will effectively seal half the system off.

Post Note-

Can you resize that picture? its incredibly large...

 

[Kenworth]

As stated above remove thermostat,turn heat all the way up front and back,open block drain,rad drain, put hose in top of rad, start motor and let run flush till it's clear,the end.a lot of times that block drain clogs up witch requires removing valve to clean.good luck be a good time to replace thermostat anyway that thing has got to be in bad shape

 

[JBurt]

This seems like an appropriate thread to ask this question. When you flush a radiator like that with your hose, what do you do with the drain water? I would assume that the concentration of coolant will be minimal but it is common practice to let it go to the gutter? It seems very difficult here to find places that will take used coolant.

 

[thor999]

Drain the system, fill with white vinegar, idle engine for 15-30 minutes (make sure thermo opens and top hose is pressurized) then allow to cool, drain and fill with distilled water. Repeat process with distilled water a few times but you only have to get the thermo open for a few minutes for this part of the process. The hot vinegar should clean the system completely and remove debris, then the repeated filling and emptying with distilled water cleans everything out and returns to neutral.

 

[shotgun_willie]

Tonight and tomorrow, I'm gonna try and get this coolant system up and running. I drove the 4runner up to the auto parts store and it was overheating pretty quick. I bought a new thermostat cause it was cheap and figured it couldn't hurt. I'm hoping I'm not looking at a new water pump or radiator but it is what it is.

I think the PO may have been lying about the radiator being replaced in the last 6 months, but I guess I should've figured as much when they weren't able to show me the receipts. :shrug:

 

[shotgun_willie]

Got everything up and running and it seems like the coolant system can be checked of the to do list for a bit. Just wanted not one last thing for reference, in case someone comes accross this thread in a search.


The picture posted earlier of the block drain is not accurate for my 1997 4runner. The bolt shown is there but there is no visible drain below it. If you loosen the bolt part of the way coolant will drain from a hole beneath the bolt ( it is 14mm). It's hard to get any kind of tubing on that hole so I got coolant everywhere as it drained.