Hey guys, I was wondering if someone could help me on this.. This is my 4th nissan but my first KA24DE, I'm the proud owner of a 1992 240sx se with super hicas. My question is regarding the cooling system. Is it normal to see bubbles coming up in the backup prestone tank under the hood when I stop my car ? It's like the prestone is boiling. I replaced the thermostat and prestone but the problem persists. I verified the compression and when the engine is hot I get a solid 180 in each cylinder even though the car has 135000miles. One other thing I should mention, I hardly get any heat when I put the heater on inside the car... Any help would be greatly appreciated...

Scy

does the car overheat at all?

mine was doing the same thing, and it was overheating. turned out I had a huge airpocket in my cooling system.

I let the engine get nice and warm (well almost hot for that matter).. took a couple towels, placed them over the radiator cap and took it off.(BE VERY CAREFUL!!....do this VERY slow)

let all the air escape, added water... made sure to top it off and saw a nice current of water.

that was that. put the cap back on and it was fixed

but, this may not be the same issue you are having

You chould have a clogged cooling system and/or air bubbles. There should be no air in ur cooling system. I'd suggest doing a radiator flush. If you lived in Saint Paul... I'd give you a free radiator flush as I currently work at Jiffy Lube.

I actually drained and flushed everything last weekend but the problem is still there, the car doesnt overheat at all !! It did before the flush, once but not again.. I'll try to removed the radiator cap when hot.. with a couple of towels... Could it be that the heather core is blocked and itS creating that problem ? cuz i dont get much heat when i turn it on.. even when it's 100 outside.. hehe

Saint-Paul ? where is that... IM im Montreal, Quebec, Canada.. hehe

Scy

Be very careful removing the cap when the engine is hot, you could spend a couple of days in the burn unit. Let it cool and try bleeding it at the bleeder on the intake man. where the upper rad. hose goes in.There should be a little gold sticker by a bolt with a copper washer under it.Remove the bolt and put a funnel in the rad. and pour coolant in the rad. until it comes out the bleeder hole steady with no air bubbles. Put the bolt in and recheck. Don't forget the simple things like checking the rad. cap if it hasn't been done. A bad rad. cap will cause it to boil over.

I would do the bleading with loosening the bleader bold. That is the correct way to do it. If you don't have a bolt all you do is loosen anything that is at the top of the engine. You put a funnel in the rad and then fill it up and then crack open the thing you are opening(hose, temp sensor,...) and wait for all the air to come out, and then close everything back up. One other thing that is possible is that you have a leaking head gasket. Sorry to say it but is possible. You can usually tell that if you dissable the ignition( so it won't start) then take the radiator cap off and fill it till it is running over. Then have someone just crank the engine over and you watch for any bubbles coming up through the radiator filler. Hope this helps.

How do I test the rad cap ? And could it be possible to have a leaking head gasket even with a very good compression ? 180 in each cyl... ?

thx again guys..

Scy