I've got some coolant leaking ('96 4Runner 3.4l) from the water pump area (assuming) as pictured below. Is there anywhere else coolant could be leaking from in the area? Or am I safe to say that I've got a bad water pump and or seal? It's got 220,000 miles on it.

 

Head gasket could be seeping coolant. More likely to be water pump, a bad radiator hose, or a pin hole in radiator squirting coolant out.

How much coolant are you losing and replacing?

 

I've traced all coolant lines and radiator and those are clean. So I fear head gasket now that you mentioned it cause the oil analysis report that I got back was speaking to coolant in the oil due to a possible head gasket issue. And the water pump is still a possibility as well.

I am not sure how much coolant I've lost. However the expansion tank was close to empty.

 

Have you checked the radiator cap?

 

Yes, I replaced it.

 

After smelling coolant burning off, but unable to find it and a very slow usage of coolant the used oil analysis said I had slight amount of coolant in oil. They were right....a external HG coolant leak hidden under the intake manifold and a slight internal leak too.

 

How's it,

I've been lurking on a few forums for a while now and have solved many of my issues with all the advice shared and given by all the awesome tech heads on here. I finally figured though I would have to start my own thread because I've looked high and low with no avail, that is until now!

I have a very similar coolant issue too, it's wet exactly as pictured. Just below the tstat on the lower front side of the engine block. Made a newb move and thougt the tstat needed to be replaced. Installed the new one with gasket, poured a gallon of coolant into radiator, and watched my truck piss itself. The coolant came pouring out just as fast as it wAs pouring in. Was able to drive it home with no problems or temperature fluctuations.

This all started after I was stuck in bumper to bumper traffic, crawling on first up a moderate hill on my way home. Got over the hill fine, sat in neutral down the hill (still in traffic) and then opened her up on the flats once traffic lightened up. Was going about 45 when I saw how got my engine was getting. As I was pulling over the gears wouldn't shift. Pulled over, opened the hood and carefully opened the radiator to cool off. Let it sit for twenty minutes. Filled the radiator up with water and she wouldn't start.

Got a tow from my uncle to his house, and let it sit for a couple hours before trying my hand with the tsat.

Today I took off timing belt cover and w/p looks fine, no wetness around seals. Also took off skid plate and checked lower hose just behind tstat and below alternator, runs from front to back of engine, all looked well there too, a little wet but no visible tears.

I've been trying to find other threads that have similar issues and all I have come across is possibly w/p weep hole or freezer plugs? Or am I being naive and is it the HG?

Will be standing by. Aloha. Nvw324.

01 Taco
3.4 4x4

 

Well first I'd say never open the radiator when the truck is hot, much less overheating. "Carefully" or not. I don't even see why opening it would help.

So you incorrectly installed the t-stat? It was just weeping before, but after you replaced it, it was pouring out?

Have you checked to see if there's coolant in your oil? I'm guessing you have an automatic?

I don't know all the things to check since I'm new to these newer trucks and there are a lot more variables involved in what would keep it from starting, since they're more computerized than I'm used to.

But yeah obviously get the thermostat installed correctly. I guess I don't know about these engines, but on all my "R" series Toyota engines, the freeze plugs were on the sides of the engine, not the front.

But to restate, in chronological order...you were driving in stop and go traffic, up a hill, back into traffic, started to overheat and wouldn't shift (auto tranny, right?), then after sitting for 20 minutes, it wouldn't start. You replaced the thermostat and did something wrong so coolant was pouring right out. No visible sign of water pump leaking or major leaks at hoses.

Correct?

 

No, I correctly installed the Tstat. Its a manual transmission. Below is the chronological order of events.

1.stuck in stop and go traffic on hill.
2. truck over heated to the point that I had to pull over. (when pulling over gears started locking up on me)
3.opened up radiator, bone dry.
4.got tow to uncles. truck wouldnt start
5.replaced tstat (correctly)
6.with engine off - poured in coolant (watched it pour out simultaneously)
7.couldn't tell where it was coming from. (definitely not from tstat)
8.drove home with whatever fluid could keep. no problems on drive home. (ten minutes drive at night, average speed of 40mph)
9.next day took off timing belt cover, couldnt see any wetness from water pump seal
10.checked radiator hoses, all looked okay. no visible tears where it could pour out so dramatically.
11.what should i trouble shoot next? theres no oil mixed in coolant.

I only mentioned water pump weep hole and freeze plugs because those may have the ability to drain the coolant so rapidly yes? no?

standing by. nvw324.

2001 tacoma
3.4l v6
4x4

 

Gotcha.

My knowledge of these trucks doesn't include anything related to an overheating engine that would cause the tranny not to shift...so I'm lost there.

I would think that if you've got the timing covers off, and you poured in coolant while someone else watched (somehow out of the way of the coolant but close enough to see), that with how much you're losing, it would be impossible for them not to tell where it's coming from.

 

How's it, do you recall where the external leak was below the manifold, and how did you remedy the situation. I believe through the pictures I may have the same issue.

Standing by. Nvw324.

 

The passenger side head gasket had a slight weep near the rear cylinder that was visible looking in through the wheel well. the The bigger leak was along the inside edge hidden by the intake manifold and it was filling the valley between the heads...performed a complete head gasket replacement job 20k miles ago.

Have you pressure tested the cooling system? Often local parts stores have a pressure testing kit you can rent and once you pressurize the system any external leak will likely be fairly obvious provided it not obscured by intake manifold or such.

 

Wow, NVW324 step away from the vehicle. If you see fluid pouring out as fast as you pour it in you should be able to determine the source of the leak... If you drove the vehicle until it had no fluid in it you most likely warped the head(s) and squeaked the pistons so the engine is dickered as it won't last 5 minutes without fluid. Once all the fluid has drained out of the motor the temp gauge no longer works accurately in any way, there is a short window to catch an overheat issue well driving before it causes engine damage, sounds like you missed that window. I'm guessing your shifting issue was due to the engine seizing.

By your first description of events you changed the t-stat had a huge leak and drove off with little temp fluctuations?

"Installed the new one with gasket, poured a gallon of coolant into radiator, and watched my truck piss itself. The coolant came pouring out just as fast as it wAs pouring in. Was able to drive it home with no problems or temperature fluctuations"

 

Yes, engine worked find. No hard shifting. No loss of power either. Haven't drove it since. Just sitting in my garage till I can find some time to get into it. I suppose I should start with a compression test. Yes ?

 

Hey guys, took the timing belt cover off. Filled the radiator and spotted the leak. It's the water pump weep hole. Ordered aisin timing and w/p kit off Amazon. Let's you know how it goes. Nvw324