father2nate

I have an issue - go figure. My car started running hot. I checked the coolant level, and was low. It seems that I have some sort of leak in the back of the engine. I looked and couldn't see anything obvious. The only thing I noticed was a piece of gasket, not sure where it came from, and it could be 10 years old. So, what is back there that would leak?

Chris_924s

Bump..

Jonathan, are you sure it's leaking- (leaving a coolant spot on the ground/ belly pan)- or possibly loosing pressure- and sucking in air when it cools creating air pockets in the coolant- my toyo did this

also- check your overflow cap on the resevoir, thats been know to be an issue.

tifosiman

An overflow cap isn't going to make coolant leak out of the back of the engine.

Father2nate: Look at the following diagram. Parts# 22-24 are located at the top rear of the motor at the firewall area. It is not uncommon for one of the hoses to split, or the heater valve to die and leak.



That is the first thing I would check.

Good luck.

brad-cam

Jonathan - scary thought, but have you replaced the head gasket yet ? Could be a very small leak at the head gasket. How long does it take to notice a loss of coolant level ? Keep in mind that the level in the overflow tank will vary a little depending on the temperature of the engine (ie. hot or cold).

I have many issues with the cooling system but finally have it working - knock on wood !

Granite 944

If you don't see anything obviously leaking back there, you may find it only leaks while under pressure, so it might not just jump out at you by looking around. This is where a coolant pressure tester might come in handy. They also work real, real well for bleeding the air out of these closed systems. I bought a Stant coolant pressure tester, and was amazed and pleased to see how well it worked for this, and for finding all sorts of small leaks that I would never have know existed otherwise. You pump up the system to about 10psi, and start looking, if theres an external coolant leak, it WILL become apparent. I think the kit runs around $80.00 if you look around. Do a search for the Stant pressure tester, and you'll find out what model number it is. I just don't remember right off hand. Just another invaluable tool to have around, when working with these cars. And other cars too.
I also agree with tifosiman.

Good luck!

father2nate

I haven't noticed a puddle under the car. I do notice that it only leaks under pressure. I will take a look at those hoses in the diagram. Thanks guys! I will let you know what I find when I take a look at it tonight.

father2nate

Got home, looked at it again. I can't tell where in the hell the coolant is coming from. I have attached a picture, maybe this will help.

Is the hose with the arrow to it a coolant hose? Should it be "fat" like that?

Also, I have a shot of that mystery gasket. It's not very bright down there, but who knows.

tifosiman

That is a cooling hose. It does look a little bloated. It looks like there is coolant residue directly below that bloated hose. It is difficult to diagnose over the internet though. Look for other signs around it of leakage.

Granite 944

Yes, its the head to the heater valve hose. Its typical for these hoses (and others) to get "fat" as they get older and weaker. It may be a good time to start thinking about a replacement hose, and maybe even replacement of the heater control valve just aft of this hose (take a good look at all those hoses back there, including the heater core hoses). As far as the gasket material goes (can't tell/see anything from the pic) , it may be some material from under the fitting that the "fat"hose is connected to on the engine side. Theres a D gasket under the head's coolant fitting (which also houses a temperature vacumn valve) right there, that may be the source of that gasket peice, and possibly your coolant leak.
PS: be carefull so as not to break/damage those speed/ref sensor connectors, and the brittle plastic of the O2 sensor.

luckett

If you've gradually lost coolant over time then there has been air introduced into the system. Try bleeding the system first to see if that solves your overheating problem. But it wont solve the leak...

Looks like it's time to inspect/replace the coolant system rubber if you have hoses that look like that.

Jonathan:
Are you going to make it up to SF on the 17th? We can take a look at it then.

father2nate

Well, It looks as if that rear hose had a gash in it on the underside. I removed it and will be replacing it.

Also - much to my dismay, I think I found the source of my missing idle issue. It appears as if the delicate plastic part on the O2 sensor is broke. I don't know when or how it happened. I have been having this idle problem for a while. Anywho - I don't want to shell out the $200 for the new kit, how can I fix this?


Chris - It looks like the upper and lower radiator hoses were changed recently, but not the little ones. I am going to fix this one, and we will look at the others when I am up there on the 17th. I got your PM, and yes I will be there and I want to check the tension on my belts.

Thanks!

aeronautica86

I had this problem about a year ago...kept losing coolant in the back and couldn't figure out where exactly it was coming from; turned out to be the heater valve, #23 in the diagram posted by tifosiman

luckett

you can just spice the wires or add some other kind of connector.

father2nate

More to the saga. Now that I have that new hose on the freaking temperature slider on the climate control unit won't go to cold. It will slide inbetween half-way and hot. The cable on the heater contol vavle is free. What the Frick? Do I need a new HCV and how hard it that to install? Looks tight back there. Also, should the HCV move or should it be stationary? Mine has a lot of play in it.

kgelles

The HCV may need to be replaced. They are designed to fail in the "hot" position. That way you do not freeze to death on a cold winter night if you are stranded in your car. They cost about $30 and are easy to replace.