likelyhood of a blown head gasket

[EMB1230]

I noticed recently that there is colorant oozing out of the front left corner of the engine, where the head meets the block. oil looks normal, no white smoke, and it's not overheating, A few months back I replaced the t-stat housing and coolant sensor, could I have screwed something up doing that?

 

[Insanejughead]

Clean up your engine while it's cold so that there is no oil or coolant anywhere on the front of the motor. Then start it up and watch for leaks as it warms up. Has the head ever been taken off that you know of?

Check your plugs, too. They could give you an indication of whether or not the coolant is getting in the cylinders. I don't know how much coolant it takes before the exhaust starts to change, but it's good that you have already checked that.

You'd have to be super stupid to mess up the t-stat and housing. It will only go in one way. Same goes for the coolant sensor; as long as it isn't leaking around the threads, then it's fine.

 

[EMB1230]

like my info says it's a 96 with 136,000, pretty low for it's age.

 

[EMB1230]

No idea if the head had ever been off, took the plug out closest to the leak, looks like a normal wear on a plug to me.

 

[Mark_88]

I've had a water pump seal go on me and the coolant was actually hard to trace to it...because with the fan blowing it all over the place it sure can look like it's coming from many possible openings...

Like was mentioned...clean the engine and run it without driving to see if you can spot the leak...

 

[Insanejughead]

The pictures of your plugs are blurry... Also, if they are super clean, then that could be a sign that there is a very small amount of coolant getting into the engine. Coolant and water vapor in an engine raises combustion temperature, and does wonders for cleaning the chambers. Too much causes problems, though. The most drastic being hydro-locking your motor and ruining pistons, connecting rods, and even crankshafts.

The last turbo motor I bought had a coolant leak into cylinder 1, and the top of the piston and the chamber were nice and clean and shiny. However, it raised the temperature of the combustion chamber considerably because the top of the piston was also melted (part of it was seared and scored into the cylinder wall). The head gasket had also taken a hit, and the gasket material no longer existed between cylinders 1 and 2. This partially cleaned piston number 2 in a nice little fan shaped pattern.

However, I did not like having to pay a machine shop the extra money to bore out my cylinders .40" over because of a failed head gasket, nor did I like the painful search for .40" over pistons that were forged for the 2.3T.

 

[EMB1230]

Few months later and I still have a mysterious coolant leak where the head and block meet, also I see coolant on the water pump, could be coming from the t-stat housing, could be the front of the HG, I still don't know. Still not getting ANY of the signs of a blown Head gasket. Planning on taking it in for a compression test Wednesday.

 

[Rogue_Wulff]

A head gasket can leak coolant externally, without being "blown" or allowing coolant into any of the combustion chambers.

With all of the suggestions given thus far, I'm surprised no one had mentioned pressure testing the cooling system. This will allow for watching where the coolant is coming from while the engine is not running, making it much easier to look it over closely.

 

[cn.anglin]

definitely get the cooling system pressure checked.had a 2.5 jeep engine that was leaking about the same spot and turned out to be a cracked block

 

[PetesPonies]

I'm surprised you have waited this long. You should at least tear the front of the engine down, clean it well and replace thermostat gasket. You may know a lot more once that is done and we are only talking an hour total here.

 

[Mikel89us]

A head gasket can leak coolant externally, without being "blown" or allowing coolant into any of the combustion chambers.

With all of the suggestions given thus far, I'm surprised no one had mentioned pressure testing the cooling system. This will allow for watching where the coolant is coming from while the engine is not running, making it much easier to look it over closely.

+1 pressure testing is always the best bet in this situation

I'm surprised you have waited this long. You should at least tear the front of the engine down, clean it well and replace thermostat gasket. You may know a lot more once that is done and we are only talking an hour total here.

+1 here too, if you dont clean it up it only makes it harder to find the issue, and a new t-stat never hurt anyone, not that i know of anyway!

 

[EMB1230]

I'm surprised you have waited this long. You should at least tear the front of the engine down, clean it well and replace thermostat gasket. You may know a lot more once that is done and we are only talking an hour total here.

Well, it was out of commission for 5 months due to a brake line blowout. T-stat in it now is good, I get PLENTY of heat! BTW, the heater hose piggybacked off of the t-stat housing/water outlet, is that typical for I4's?

 

[PetesPonies]

You have a leak. It has nothing to do with whether or not your thermostat is working. Many good parts have to be removed to fix other problems sometimes. By opening up the front, you will be able to see more and figure where the leak is coming from. Remove the belts, the radiator and heater hoses and see what's going on.

 

[mattpresley]

My 1996 Explorer has had external Head gasket leak along with every other gasket on the damn engine for a few years now. I recommend simply topping off your cooling and just overhauling whole engine or replacing after it finally gives out. The cost for gasket replacement is high as it is (Unless you can do your own work) and I personally don't feel it's worth dumping a few grand into having gaskets changed on a high mileage engine when I can have a BRAND new one installed for $3,000

 

[EMB1230]

Well, I am an idiot, noticed last night that coolant IS coming from the threads of the CTS,I guess it wasn't tightened down enough or worked it's way loose, anyway I took it out, put some plumber's tape on it and tightened it down pretty good this time. lol, when I took the sensor out the coolant went right to the top of the water pump so that solves one spot, I'm crossing my fingers hoping that was also the reason why coolant was behind the timing cover, where the head/block meet on the Driver's side.