gohawks

I noticed a couple of days ago that I had a small coolant leak somewhere under my 4Runner.

I have a 1988 4Runner with the 3.0 auto trans.

Here are a couple of things to ponder:

1) It only seems to leak overnight. I can drive it in the morning and let it sit all day and nothing leaks. I'm wondering if it is a temperature issue (something expanding and contracting with temp fluctuations)

2) I've been under the vehicle several times. I cannot pinpoint where the leak is coming from. At first I thought I might have an external HG leak. But it appears wet just above where the block and the head join. I can't really tell. However the leak is concentrated where the transmission connects to the engine. It appears to get the back half of the oil pan a little damp as well. I've heard about the little U-shaped hose and it doesn't appear to be leaking. Wherever it is coming from I can't see it.

3) I have noticed when checking the coolant level that sometimes when the engine is cold (like after sitting all night or all day w/out driving) that when I remove the radiator cap the radiator appears to be under pressure and coolant overflows. Not gushing out, but definately comes out. I thought that as odd. Would the cap be bad? Its a pretty new cap. Wrong pressure of cap perhaps? I"m clueless.


any thoughts on the pressure in the cold radiator or the leak?

thanks.

waskillywabbit

iTrader: (-1)

Lots of hoses back there have coolant flowing through them, you might have just a pinhole leak that is only under pressure and if it is a heater line, might only leak when you open up the heater and pressure things up.

Checked your overlow bottle and line?

You should have it checked out professionally if you can't pinpoint the problem...coolant leaks/issues kille engines quick if they get out of control.

Saw a dead new FORD (shocker) yesterday cause some fool of a woman drove the vehicle with smoke just a pouring out the hood like nothign was happening and you could see the coolant just pouring out underneath the car as she continued to drive on down the road until the motor quit. Stupidest thing I've seen in a LONG time.

gohawks

well, i've been checking the coolant religiously.

Any idea why the cooling system would have pressure in it cold?

waskillywabbit

iTrader: (-1)

Simplest thing that comes to mind is that your pressure relief valve on your cap and overflow are not functioning correctly, thus the system is staying pressurized when cold. You might try a new radiator cap...as those things do go bad.

95ToyotaPU007

I've heard 'mysterious' leaks coming from this coolant hose connection. See attached pic.

gohawks

Well, I have continued to take a look at things and I really can't find any hoses near the top that appear to be leaking.

What I have noticed is that it only leaks during the day while sitting. What I mean is it sits all night (colder), in the morning there is no noticeable leak. However as the day begins to warm up I get a few drips under the vehicle. If I drive around during the day and then let it sit, it will not leak.

The block is wet below the head, the head appears to be wet as well, but I cannot tell for sure. The coolant seeps down the side of the block (back side), and then collects on the oil pan drain bolt, and bottom of transmission bell housing.

I'm beginning to wonder if I have some seepage from an external head gasket leak. From my reading an external leak on the 3.0 is pretty rare.

I ran down to autozone and borrowed a pressure tester. However there was no adapter to fit the Toyota radiator, so I wasn't able to use it.

Really difficult to see things from underneath.

I'm losing a VERY insignificant amount of coolant, but would prefer to take care of it the right way soon.

Thanks for the help and suggestions, keep 'em coming if you got 'em.

gohawks

This is the suspect area. The head above the block appears damp as well. I just don't know whether that is some oil from the valve cover gasket weeping or if is coolant as well. I do know that this is the spot where the leakage/seepage becomes most significant.

yota_krazy

has it had the headgasket recall done? I have seen them leak oil externally, not coolant tho but its possible. Hook up a pressure tester adaptor to the radiator neck and pressurize the cooling system. Then look for leaks.

gohawks

Well I planned on doing exactly that. I went down to Autozone and borrowed their pressure tester. There was no adapter however to fit a Toyota radiator.

No other parts store has a pressure tester to loan, at this point I am way to o cheap to buy one.

No headgasket recall done. Mine never had one according to Toyota corporate.

yota_krazy

ok. let us know how that pressure test goes. Also, once you pressurize the cooling system, try wiggling around some of those coolant hoses on the backside of the plenum. It will help you pinpoint a little pinhole leak.

gohawks

Anyone wanna venture a guess as to what this might be that is leaking? This pic is actually from 5 months ago, so I've had this problem longer than I initially thought.

Only in the past several weeks have a let my truck sit for a long period of time for something to actually drip on the ground.

thanks.

yota_krazy

if that is the drivers side like i think it is, there arent any coolant lines on that side...unless its one from the throttle body or something. Kinda looks like an external leak from the headgasket. Hard to tell tho

Rory

dude. If you won't take it to a professional, for god sakes go to sears and get the cheap pressure test kit. You can't afford $100?? Just wait till you blow the engine, it'll be more. If you won't take it to a professional and you won't purchase the right tools, it won't get fixed. It might be leaking from a TON of places and nobody on this forum will solve it for you.

Buy the pressure tester! I have used mine a crapload between my friends and I.

gohawks

Rory. Sound advice. A couple of issues however. 1) I do not have $100 for a pressure tester right now. I will call autozone's in the area until I find a free one I can borrow. 2) I would very much like to take it to a professional, I don't have one locally however that I trust. I will have to take it 100 miles away, and they aren't open on Saturday so I don't know when I'll be able to get it there.

In the mean time I realize now from the pic that I have had this issue for 6 months at least. In this time the amount of coolant I have lost is minimal, not even enough to drop it below the low level mark on the overflow tank in 6 MONTHS.

I check the level religiously, I keep a keen eye on the temp gauge, and watch for all the tell tale signs of an internal gasket issue:

I have no white smoke out the tail pipe. I have no coolant in the oil. I have no oil in the coolant.

All that said it may let loose on me and I may blow it up tomorrow, but if so there isn't much I can do about it due to money right now. So for now I'm just gambling that it won't develop into a major problem rapidly.

I'm not expecting complete resolution from the board, after all they cannot fix it for me. However, I am soliciting probable/possible explanations other than those I have discerned from someone who may have had a similar issue. Often peoples suggestions on the board have pointed me in the right direction to look and helped me identify a more simple, cost effective solution to my rectify my problem.

gohawks

Pressure tested this morning. Starting at 7:00 am. Held pressure until noon when I left, vehicle was then moved outside and low and behold three hours later the problem evidently reared its head.

A leaky heater valve. They didn't have one in stock so I may just do it myself. It looks pretty straight forward.

Evidently at just the right temperature this valve would leak and drain down the back of the head and block on the driver's side.

A pricey part $40-$80 depending on source, but obviously much cheaper than a BHG or a leak under the intake.

04 Rocko Taco

Excelent work tracking it down, congrats, let us know how the repair goes!!

waskillywabbit

iTrader: (-1)

Glad you found the problem and it is readily and cheaply fixable...compared to a HG.

gohawks

I would like to take the credit for it, however the autozone in town didn't have an adapter for the tester to fit yota radiator. I broke down and took it to a shop.