Heater core exploded!!!

[big-phil]

I bought this 78 280z about 2 weeks ago, car runs fantastic! untill tuesday night at a stop sighn. I take off hard in 1st, then 2nd, almost to red line, and BOOM! all my windows fog up, coolant is spitting all from behind the dash, and the smell of HOT coolant smoke fills the car. I pull over, I'm not far from home, and I see what just happend is not good, so I drive home. The motor temp never gets to 250f , But after I get home I lift the hood and see some leekage from between #3 and #4 piston (just above the oil filter) Now I know the heater core cracked from the pressure, I think this was going to happen at anytime because I could always smell just a hint of coolant in the car, so it must of had a very small leak, and the pressure poped it. But the head gasket, was that from driving the car home hot? It never actually touched the red 250 mark. Oh, and there is now white smoke comming from the tail pipe, so for sure head gasket is gone..... Today is thursday, and the car is all tore down already for a new gasket, I like to fix stuff ASAP. I ask this question because I stunt a street bike, do shows...stuff like that I have a 2001 honda cbr 929, my temp has gotten to 265 many many many many many many many times, and the bike still runs. was it the age of the car, and the 153,000 miles on the motor that did it in?????? Anyway hope to have the car on the road by next week.

[Mr Camouflage]

I'd say that the head gasket let go first when you redlined the engine, letting the combustion force into the cooling system, overpressurising the cooling system, which found a weak point to blow open - the interior heater core. Thats my theory. If theres water in the oil, then its a good bet thats what happened.

But I could be wrong. Also the temperature guage measures the temperature of the water in the engine. If theres no water in the engine, then the temperature guage wont work , or will give a inacurate low reading.

Good luck with fixing it. Check that the head hasn't warped.

[big-phil]

a pic of the 929

[big-phil]

I bet your right! I just calld autozone and a head gasket is $15.99 I left the intake, and exhaust manifold on, unbolted the exhaust at the header, so it will all come off in one part so I wont need any more gaskets, and the valve cover gasket looks good I'll just put a little sealant top and bottom, so I'll be out the head gasket, coolant, oil change, and a heater core is $59.99. I was thinking of taking the heater core to a radiator repair shop to see if it can be fixed???? I don't look foward to taking that out, the car has (ICE COLD!) a/c can I get that core out with out messing with the a/c?

[Bambikiller240]

So you are just going to assume that the cylinder head isn't warped from this blown head gasket situation?

[Zs-ondabrain]

TAKE THE HEAD TO THE MACHINE SHOP!!!!!!!!!!

re-surface the head or your just asking for the gasket to blow again, TRUST ME. Been there done that, HATED it.

When it comes to your Z, Always take the extra time and money to do it right the FIRST time, Or you'll be spending twice that the next time.

The $16.00 head gasket is not the one you want, The right one will run ya about $50 or more. The valve cover gasket is the only thing that should cost about $15.00.

My 2Cents.

Dave.

P.S. Where in the h%$# did you fing a heater core for $60??

[Ed]

I'll put in my $.02 also. I've also had the missfortune of blowing a coolant hose. I had steam coming from the engine bay, I noticed the temp was higher than normal but no where close to the 250 mark. Anyway to make a long expensive story short. The head was warped. And I'm willing to bet your head is warped also.

[sblake01]

And don't just change the core. When you're in there, check the three small hoses, the firewall connector/valve, the heater valve, clamps, etc. Make sure that you don't end up having to go in there again for a problem with the small stuff. Been there, done that! BTW, I was able to change my core without removing the a/c unit.

[sblake01]

P.S. Where in the h%$# did you fing a heater core for $60??

I hope it's not at Autozone! From personal experience, I would suggest not buying any 'hard parts' for a Z or any other early Datsun from there or any of the chain stores. You'd be much better off having your old core redone at a radiator shop. If Autozone can't get a fan clutch right (and believe me, they can't) I doubt if they could get a heater core right.

[Bambikiller240]

I hope it's not at Autozone! From personal experience, I would suggest not buying any 'hard parts' for a Z or any other early Datsun from there or any of the chain stores. You'd be much better off having your old core redone at a radiator shop. If Autozone can't get a fan clutch right (and believe me, they can't) I doubt if they could get a heater core right.

But, doesn't Jesse James buy all his parts from AutoZone?

just kidding you Stephen, I wouldn't buy anything from AutoZone (unless it was a liquid that came in a sealed container from a nationally known company) I love a bargain as well as the next guy, maybe even more, but that $60 heater core and $15 head gasket...............well let's just say I'd never gamble on them in my car. There are other places to scrimp that make more sense to me. Price is WAY to cheap to give me any confidence that they are quality parts.

[Walter Moore]

Hey, I have a question about heater cores...

I took mine out and tested it by submerging it in a bucket of water and then pressurizing it to 20PSI with compressed air. There were no leaks that I could see, and the heater core itself looks nearly new. Would I be taking a huge risk if I just put it back in the car?

(I promise not to blame anyone else if it fails in a short time. Regardless what anyone else tells me in the end it is my call.)

[Bambikiller240]

That is the way it would be tested at a radiator shop. Does it have good flow through the core? If it will hold 20 lbs pressure and flow through it isn't restricted by sediment, I wouldn't be afraid of using it.

On the other hand, you might consider having a radiator shop remove one of the tanks from it and check it out internally. Just a thought.