Hey all. My '94 3.0 4Runner jsut started spewing coolant out of the coolant overflow today. It seemed to be running fine, then when I shut the engine off I heard a hissing noise. Turned out it was steam hissing out of the overflow line that goes from the radiator cap to the overflow reservoir. I got some 50/50 and topped off the radiator and fired it up, after a few minutes the same thing was happening, massive amounts of steam spewing from the overflow. Aside from this the engine seems to be running fine. It's got 135,000 miles on it, I just had a major factory service done to it about 2500 miles ago and it had the HG replaced from the recall at about 80,000 miles.

I'm hoping to god it's not the HG as I don't have the tools or space to do the job myself, nor do I have the $$ to get it fixed.

Thanks for any good news or insight you can shed!!!

 

So, it's not overheating? Just spewing coolant?

 

yeah, temp gauge is hanging right at about 3/4.

and not exatly 'spewing' coolant, mostly jsut spewing steam, but I'd guess if the overflow was more full it would be.

No white smoke from the exhaust either, so I don't *think* its a HG issue.

 

3/4 is over-heated.

 

I'd check all the usual over-heating suspects.

-Thermostat
-Radiator
-Fan
-Water pump

Let's hope it's not a blown HG.

 

well, its closer to half-way between 1/2 and 3/4, probably clsoer to 1/2, and well below the red indicator on the guage.

 

When's the radiator cap been replaced last ?




Fred

 

These Toyota factory temp gauges are designed to stay in the middle through a large range of temps. Anything over 1/2 is not normal. In 14 years I've never seen mine go over 1/2.

 

I have a 95 runner, and my temp sits right at half.

 

well after topping off the coolant and idling the truck with the radiator cap off for a bit, I replaced the cap and took it for a drive. Got up to highway speeds for about 15 minutes and when I got back home and checked it out it seemed to be okay and the temp guage hovered *just* above the 1/2 mark(like a needle width maybe).
Interestingly, the radiator drank a whole bottle of prestone 50/50 and then about another 1/4 bottle's worth of water. I'm wondering if I've got a leak in the coolant system somewhere?

thanks for the feedback so far guys, I jsut wana figure out whats up since its my daily driver.

 

Take off your oil cap and look for a milkshake-like substance on the inside of the cap. If it exists, you have a blown HG for sure.

 

like, specifically on the inside of the cap? should I do thiw while the engine is warm or after it has cooled down?

 

Yes, inside the cap. It doesn't matter if the engine is warm or cool. The milkshake will be caked on the inside of the cap regardless.

 

Check the functionality of your thermostat. There seems to be either a lack of flow in your coolant system, or inadequate cooling. My 93 T4R sits right under 1/2 normally. Make sure you are filling your radiator when the front of the vehicle is higher than the pack (pointing up a hill) to eliminate possibility of air in the system. Check your fan clutch. Check the function of your water pump. Easy way to do that is to pinch the upper radiator hose for a couple of seconds (after the engine is hot, of course). When you release the hose, you should feel a surge through the hose. Is there any other condition causing this? A/C? Sitting in traffic only? Etc?

 

well I topped the coolant off with the truck sitting on an incline and ran the motor for about 10 minutes with the cap off and the coolant level stayed about the same. Replaced the cap and tried pinching the upper radiator hose as suggested and there was indeed a surge when I released it.
The inside of the oil cap looks fine, no milky milkshake looking substance and for the past 2 days with light driving the temp gague has stayed just a c-hair under 1/2.

Seems like the motor had just consumed a good amount of coolant over the last 1500-2500 miles or so, so it was running thirsty. Strange though that there's no white smoke (to suggest a BHG) from the exhaust aside from a faint bit when its first fired up.

What else might cause it to consume so much coolant (with no apparent leaks underneath it when its parked) and how else can I check to make sure its not a BHG?

Thanks all!

 

You could always do a compression test.

 

Sounds like you are losing alot of coolant. If you are positive it's not leaking it then you are losing it internally. You probably have head problems, a cracked head, blown headgasket or a corroded water jacket maybe. When my head gaskets went, I used no more than a half gallon over 2-3 months before I finally got the milkshake under the oil cap.

 

Mine began to go through coolant for a few weeks before the HG blew. I didn't have the milkshake warning, though.