Puzzling Cooling System Leak

[Tham]

My KE70's 4K engine's cooling system seems to

be having a slow leak, about 100 cc a day.

 

The expansion tank level would go down about half

to one inch every morning.

 

Several mechanics searched high and low for the source

of the leak - water pump, expansion tank itself, radiator,

hoses, head gasket, etc, but couldn't seem to find any.

 

They ran the engine at idle at operating temperature for

quite some time, then switched it off and let it cool down.

The level in the expansion tank, as well as the radiator cap,

stayed constant. The radiator remained full up to the cap level.

 

However, the expansion tank level would go down half

to one inch by the next morning. The radiator remained full,

meaning it had sucked off the loss from the expansion tank.

 

One of the mechanics suggested that maybe it was minor

head gasket seepage or crack in the engine block which

could not be detected, or even a small core plug leak

which was out of sight, perhaps in the rear block

housing with the gear box.

 

Might pouring half a bottle of Wynn's Radiator Stop-Leak

No. 68627 help ?

 

I've heard that Holts Radweld tends to clog engine and

radiator waterways.

 

Thanks to all the good people here.

[furryfrog]

did any of the mechanics try to pressure test the cooling system?

[DearmanKE]

although stop leak isnt usually recomended because it can block up bits in your radiator making your cooling system less effective i had this same problem in my old ke70.

 

i used stop leak and it worked fine, the car would get a bit hot on idle, but it did that bfor i used stop leak anyway. so yeah

[WinKE55]

Pressure test the cooling system.

 

 

I am pretty sure you can get a dye that you can put in your cooling system and I THINK you need a UV light, it will show up the leak in no time at all.

 

 

As you should know, if the car is filled up when hot, the water inside is already expanded a bit so in a cold morning the water will come down a bit. Though what you say is a little too much for that

 

Try looking under your engine oil cap, have a look to see any bubbles, thick milkshake kind of substance. If so, then head gasket is blown.

[dashills]

hey , is your right hand front floor wet if so its your heater core . the same thing happend to me a about 9 months ago

so turn your car on and turn the heater on once its hot check for water on the floor

 

 

good luck with that one

[ke30Rolla myles]

the same thing happend to me when i changed my engine i split the heater hose and my floor filed with coolant so i blocked the hose off made it run back into it self but now i have to keep topping up my water in the coolant, every time i start my car it sounds shit and sounds like there is water int he psitons then once i rev it all the watr clears it runs like normal i have replaced the head gasket 2 times but seems to be sitll doing it:(

[DearmanKE]

cracked head?

[WinKE55]

hey , is your right hand front floor wet if so its your heater core . the same thing happend to me a about 9 months ago

so turn your car on and turn the heater on once its hot check for water on the floor

 

 

good luck with that one

 

 

That could be pretty good idea to check to. Can't believe I missed that! :D

 

 

keep us informed on what it was =]

[philbey]

Sounds like a fairly minor head gasket issue. I've had them where they are using water, but show none of the other symptoms of HG leakage for some time. I drove my CA18 turbo for months suspecting the gasket was leaking (similar issue, used small amounts of water) but only occasionally would I see excessive steam out the exhaust on cold mornings.

 

When I finally got Cappucino froth in the radiator, I changed it. I wouldn't worry about it that much until you see that.

[DouggehKE30]

On my 5k I kept losing water for ages I had no idea where it was going, presure tested a couple of times, then pressure tested it again and suspected the welsh plugs, took off the manifold and found the the block had a decent crack down the side, thus leaking water. But it only seemed to leak every now and then. It was easy too see mine, as it had large rust stains down the side.>Pic of crack<..allso next page.

 

Hope this might help narrow it down.

[philbey]

Probably an engine temp issue, it may close the gap due to expansion of the block etc.

[Tham]

Thank you for the good and very useful information, everyone.

The people in this forum really know their stuff.

 

I'm from Malaysia, so none of the cars are fitted with heaters

here. Both inlet and outlet pipes (to the left and right of the

water pump) are plugged off with 15 mm rubber plugs. The

same with my Opel Gemini years ago. These plugs usually

have to be replaced every two or three years.

 

Most mechanics in Malaysia are quite "primitive". Other than

those big service workshops belonging to dealers or assembly

plants, hardly any small-time mechanics have tools like

cooling system pressure testers or torque wrenches, let alone

radioflourescent dyes or UV lights. One of them did have a

pressure tester, but he had misplaced it.

 

Well, I took it to another "primitive" mechanic two days ago,

who still repairs my engine every now and then. He and his

apprentice, using only their eyeballs, looked all over the

engine very carefully for the leak. His appentice boy crawled

underneath, and finally managed to spot what appeared to

be some wetness lower down the rear of the right side of the

engine block, below the intake/exhaust manifolds. Looking

further up, it appeared to be coming from the last core (welsh ?)

plug from the end of the block.The plug was rusty. From above,

this plug was blocked from view by a heat shield.

 

Replacement it was quite a major job. The starter and

manifolds had to be taken out to reach this plug. The plug

cost just M$5. He hammered the old plug a few times, it came

loose, and the coolant burst out, which looked quite murky

and rusty even though I am using good "Valeo" brand coolant

(thought these had good rust inhibitors ?). I forgot to ask him

to insert a hose into the radiator cap to flush out the rest of

the old coolant.

 

Anyway, the next day, looking at the expansion tank,

the level appeared to have dropped half an inch again.

I'm not sure, this could be due to some small air pockets

still being left in the block after they had filled up the

radiator with new coolant and water.

 

Or the head gasket might also be having a minor leak, as

Philbey suggested and experienced. I also occasionally notice

some condensation from the exhaust on cold mornings, or

cold rainy days.

 

Thank you again for all the help.