Auto Help: Blown Head Gasket or Not?

[CowboyMcCoy]

I have a problem with my 97 Sentra overheating. I'm unsure if it's a blown gasket, although I have used liquid copper and that has not fixed the issue. My car keeps overheating... and blowing hoses. I fix the steaming hoses and then it overheats every 20-25 miles instead of every 3-4 miles. Then, after a while, I'll blow another hose and the reservoir is bubbling and you can hear hissing noises coming off the hoses. Could this be gas from the engine or pressure from the thermostat? Does the liquid copper really work? I almost bought a more expensive type of gasket leak repair, "Blue Devil, but it was 50 bucks as opposed to 10 and someone I know recommended the liquid copper.

Could really use some help here.

 

[CowboyMcCoy]

Update: I'm convinced it's a blown head gasket. A friend, who is a reputable mobile mechanic, quoted me 250 for labor and 100 for parts. I assume this is a good deal based on my previous knowledge of this type of repair.

Thoughts?

 

[Viper]

check your oil, if you have water in your oil it's a blown head gasket. this sounds more like a waterpump.

 

[Tabascocat]

check your oil, if you have water in your oil it's a blown head gasket. this sounds more like a waterpump.

Agree, check the water pump.

 

[CowboyMcCoy]

Wouldn't the water not pump through at all if that's the case? Bubbles are coming out of the reservoir. And when I put water in, and the hoses are all working, it goes for a good 20 miles. Once the hose blows from all the pressure, it overheats almost immediately. I'll look into it though.

 

[Vtwin]

Did you verify the thermostat is not stuck closed?

 

[tantrix1969]

Did you verify the thermostat is not stuck closed?

yep check this first

 

[CowboyMcCoy]

How would you check the thermostat?

 

[Kendo]

Have you noticed any significant power loss and/or are you losing coolant? Blown head gaskets seriously affect performance. Sounds like a radiator problem to me. Could also be as simple as a bad radiator cap. Thermostats typically stick open or closed and stay that way when they go bad. If stuck closed you would overheat way before 20 miles. Same with a bad water pump. I would look into the radiator before going down the head gasket route, although a bad radiator has been known to lead to blown head gaskets.

 

[CowboyMcCoy]

Yes, I've noticed about a 20% loss in power, I'd say.

Since there are bubbles in the reservoir, doesn't that mean head gasket?

I'm lucky, though, a guy I know can fix it for $350. Which is pretty good from what I understand.

 

[Warick]

 

[Tabascocat]

The more I think about it, sounds like the water pump is not the culprit. When that goes out, you are usually left high and dry. Rarely, is it a problem that takes time to go out.

 

[tantrix1969]

How would you check the thermostat?

pot of boiling water, but missed where you said you bubbles in the reservoir- this does sound like a blown head gasket or heater core could have a small leak(you dont feel moistness in passenger footwell do you?) . One more thing is you might want to flush out radiator(would just refill with water to test) due to having used stop leak, Ive gotten crud from it before that blocked up one of the passages, and the easiest thing to try is change the cap

 

[MyBad]

Radiator could be filled with sediment, crap, and not allowing much water flow. The liquid copper may have plugged your radiator.

 

[CowboyMcCoy]

pot of boiling water, but missed where you said you bubbles in the reservoir- this does sound like a blown head gasket or heater core could have a small leak(you dont feel moistness in passenger footwell do you?) . One more thing is you might want to flush out radiator(would just refill with water to test) due to having used stop leak, Ive gotten crud from it before that blocked up one of the passages, and the easiest thing to try is change the cap

I used the "stop leak" to fix the head gasket, temporarily. That stuff didn't work though. And I'm convinced it's the head gasket after reading all of this and talking to the mechanic. I'm just glad it's a reasonably priced fix.

 

[Vtwin]

The "blowing hoses" part is odd, isn't it? The pressure shouldn't build up that much before the pressure relief valves on the cap/reservoir open. I've had more than one car with cooling system problems but have never seen a hose blow. Are they blowing at the radiator side or the engine/water pump side?

Now if the thermostat was stuck closed the coolant could heat up enough quickly enough to blow the head gasket which would allow some coolant movement through the system and release some pressure keeping the pressure relief valves from opening and causing the overheat condition.

How much coolant are you losing on the 20 mile ride before you overheat?

Bubbles in the res is a sign of a blown head gasket. There should also be a scum of oil on the top of the coolant. Better check your oil to make sure you are not getting coolant in the oil system.

The last rig I had with this kind of issue was a Subaru Forester with the 2.5l Boxster which is notorious for blowing head gaskets. The car would run hotter than normal but wouldn't overheat to a shutdown condition. I ran it like that for quite awhile just topping off the coolant until I had time to fix it.

I don't think a stuck thermostat is your problem now but it could have caused your problem and could be contributing to the current problem. Seeing as how you need to fix the head gasket don't even mess with the old thermo and just put a new one in.

I am very curious as to how much coolant you are losing on the 20 mile drive.

Those snake oil additives are garbage and at best will only buy you a little time, at best.

 

[Denim Chicken]

I blew hoses like that once; I had put my thermostat is backwards.

 

[Vtwin]

I blew hoses like that once; I had put my thermostat is backwards.

That's what I mean. The only way I can see hoses blowing is if the thermostat is stuck shut (or in backwards). That could/will also blow the head gasket. And warp the heads if it really isn't your day.

 

[CowboyMcCoy]

The "blowing hoses" part is odd, isn't it? The pressure shouldn't build up that much before the pressure relief valves on the cap/reservoir open. I've had more than one car with cooling system problems but have never seen a hose blow. Are they blowing at the radiator side or the engine/water pump side?

Now if the thermostat was stuck closed the coolant could heat up enough quickly enough to blow the head gasket which would allow some coolant movement through the system and release some pressure keeping the pressure relief valves from opening and causing the overheat condition.

How much coolant are you losing on the 20 mile ride before you overheat?

Bubbles in the res is a sign of a blown head gasket. There should also be a scum of oil on the top of the coolant. Better check your oil to make sure you are not getting coolant in the oil system.

The last rig I had with this kind of issue was a Subaru Forester with the 2.5l Boxster which is notorious for blowing head gaskets. The car would run hotter than normal but wouldn't overheat to a shutdown condition. I ran it like that for quite awhile just topping off the coolant until I had time to fix it.

I don't think a stuck thermostat is your problem now but it could have caused your problem and could be contributing to the current problem. Seeing as how you need to fix the head gasket don't even mess with the old thermo and just put a new one in.

I am very curious as to how much coolant you are losing on the 20 mile drive.

Those snake oil additives are garbage and at best will only buy you a little time, at best.

Very good post. Obviously you know your stuff. I'll know more soon when I take it to my mechanic, who has walked me through the possible problems. I believe it's a head gasket. But that's a good thought that it could be caused by the thermostat. I'll run that by him.

 

[LittleBoyBlue]

stuck thermostat or somwhere there could be a valve in one of coolant lines that is blocked up or stuck closed (happened to me) not sure if you have that on that car thought.

Fill coolant level until its full.
Run the motor
when it gets hot feel the upper radiator hose.

If it feels hot and coolant flowing through it then its not stuck
If if feels hot and bloated and empty(no coolant flowing) then its stuck