i have a 91 toyota pick up that mysteriously leaks water, i replaced the head gasket about 3 months ago and just now started noticing water disappearing i looked all over the engine and found nothing did compression test and all the cylinders came up with exactly the same compression, no oil in water, no back firing, spark plugs looked perfect and i have looked everywhere for this leak and still no sign, it leaks about a cup of coolant about every 4 hours of use I'm baffled any suggestions?

p.s. the reason why i had to do a head gasket was because the aluminum started to wear out near the water jackets..can you believe that! i have seen cracked or warped heads but not pits from the cheap metal wearing out from normal use...cheap bastards

Is your motor properly grounded? I have heard of electrolysis causing metal to disappear. Have you pressure tested the cooling system? the cap?

yes it is grounded i remember taking the wire off while i did the head job the first time and also made sure it was directly connected when i put it back together.., now i didn't test the wire and make sure it had a good connection the first time or the last.....and no i haven't pressure tested it yet, but would that just show a leak in the system?

If the cooling system doesn't hold pressure, then there is a leak somewhere.

how can i tell if its the head or something else like a water pump.., I'm trying to avoid a major tear down again.., what can i do that will eliminate the head as the reason for the leak, i know i already have a leak so doing a pressure test would be pointless

The pressure test may point out where the leak is. You pressurize the system so you can check every hose, freeze plug, etc. without having to worry about getting burned or injured from a hot running motor. The motor is turned off when you pressurize the system. There are dyes available at autoparts stores that may also help in pointing to the location of the leak. Did you notice any water stains along the top seam of the radiator?
Is the overflow bottle full?

Definetly do a pressure check of the cooling system.

Is your exhaust white ? Do you smell coolant in the exhaust ?

Have u checked the water pump because i had the same problem and i replaced mine and that seemed to fix it.

Mine was leaking from the cap on that thing between two heater hoses on the firewall that is there for draining the radiator. The cap had melted. The next time I had a leak that would have been harder to spot, it was in that small hose under the intake. I'm not sure you can eve check that without taking off major components, but see if you can.

I would do the following:

1)Place a napkin/paper towel over the tailpipe for a few minutes and smell it or see it for coolant residue
2)Perform an cooling system compression check
3)Perform an engine compression check
4)Perform a leak down test
5)Perform a fluid analysis test by buying a fluid analysis kit for $15-20 at any local Caterpillar dealer or any heavy duty repair shop that repairs bulldozers,cats,backhoes,big rigs & more.
6)There is a headgasket recall on most of the V6 engines used in Toyota trucks & 4-Runners,see below

21 Toyota headgasket & oil sludge recall sites:

http://www.brian894x4.com/V6headgasketrecall.html
http://home.off-road.com/~kemanuel/V6-HG.htm
http://www.off-road.com/toyota/4runner/topqs.html
http://www.yotatech.com/~corey/4runner_faq.htm
http://www.off-road.com/toyota/4runner/topqs.html
http://www.babcox.com/editorial/ic/ic110028.htm
http://www.alldata.com/recall/make/Toyota_Truck.html
http://www.alldata.com/TSB/60/94601650.html
http://www.yotarepair.com/Campaigns.html (3.4L,V6,headgasket recall)
http://home.off-road.com/~bibelheime...eadgasket.html (3.4L,V6,headgasket recall)
http://home.4x4wire.com/erik/t100/3.4v6_headgasket.htm
http://www.jasperengines.com/pdf/5SFECoolantLeaksTB.pdf
http://www.nordicgroup.us/oil.htm#Toyota%20Sludge
http://www.toyota.com/about/news/pro...-consumer.html
http://www.usatoday.com/money/autos/...ota-sludge.htm
http://www.petitiononline.com/TMC2003/petition.html
http://groups.msn.com/ToyotaOwnersUn...gaskettsb.msnw
http://groups.msn.com/ToyotaOwnersUn...adgaskets.msnw
http://www.babcox.com/editorial/ic/ic100052.htm
http://www.autosite.com/content/own/...action/recalls

The dealership will give a free rental car for a day or two and replace other routing maintenance parts and only bill you for those parts.The headgasket & it's labour is of course free.

Sidney® ™
Repairs tv's,vcr's,home/car audio out of my home
E-mail:sidneybek@yahoo.com
Dartmouth,Nova Scotia
Canada
1985 Toyota 4-Runner,solid front straight axle,factory cruise control,sunroof,22R-E,W56,RN60LV-MSEK,rusted rear step/towing chrome bumper with 247 000 KM