2 weeks after doing the 3.5 swap, I had to replace my radiator. I didnt think much of it, probably just a crappy brand w/e. But what happened with that was that the metal core that reaches over and grabs the plastic tank on the top had seperated and spread away from the plastic, thus not sealing right, therefore leaking more and more as the spread became bigger.

I changed the radiator. I noticed last week, THIS new radiator is doing the SAME exact thing. The metal core is spreading away from the plastic tank. Its only a mater of time before it leaks just like the old one.

Thinking of the cooling system, the only thing that "applies pressure" to the system is the radiator cap, so i changed it, still spread. Here's the thing though, there is in fact UBBER pressure inside the radiator. When i took off the old cap, the thing flew over the car and coolant gushed like a giezer (sp*). Needless to say I burnt myself being an idiot . I had taken off the cap on the hot 3.0 motor and it NEVER did anything close to this, and I believe this is what is causing the radiator core to spread.

Here's the thing...

*if there was high pressure in the radiator, shouldnt the system allow pressure to be "relieved" by allowing some coolant to go into the overflow tank? Because that is not happening with me.

*Also, the only other thing I can think that would cause this is a blockage in the coolant passages. Any recommendations on a flush product? (i've used STP cooling system flush before, but Im wondering if there is something better out there).

Thanks for any input,

Eddy

 

One thing I could think of is that you have a coolant leak somewhere which is also collecting air into your system, so when you popped the cap open the air pressure buildup pushed through.

 

I don't know if you want to do a radiator pressure test. I think Cattman has a tool for checking this.

 

Well I recently bled out the air from the system for a good 25 mins with my high 1350rpm idle, and heater on at full blast. What started out as what I thought was a full radiator I filled a good 1/2 gallon after the 25 mins of bleeding air. I still have the bulging radiator problem though. The spread is expanding from left to right now and I estimate a week at most before it starts leaking and goes cab00m like the previous one :-(.

I dont think I need to do a radiator pressure test, its a given its under excessive pressure. What Im trying to figure out is what could be causing it.

Thanks for the input so far. Any other input from anyone??

I've been thinking of either ordering the Koyo Copper radiator from Justin's GD or ordering the Griffin aluminum unit, but my concern is that I dont want to spend that extra $ without first figuring out whats causing this to begin with.

 

I wouldnt invest in a new high dollar radiator before you fix the problem.

 

Thats exactly why Im trying to figure this out before my current radiator pops :-(

 

I had a similar problem when I put the radiator in the race car and it was caused by the hose to the catch can not allowing pressure to relieve. I would suspect the cap not allowing the pressure to relieve or the hose to the catch can is blocked.

 

hmmmm, i'll try to blow into the hose once the engine cools down to see if there's a blockage. I doubt there's a bock there, BUT perhaps at the can itself at the bottom where the hose connects.

 

Is the car over heating?

 

its not overheating yet. the only time it overheated was when the 1st radiator popped and it threw out all the coolant. I was only a few blocks away from my house and everytime the car was moving the temp would drop back to normal.

However it does run pretty hot under the hood. I'd compare it to a turbo maxima. I popped the hood on SouthFloridaTech's turbo max and the amount of heat under his hood is identical to that under my hood.

Hmmm, I guess higher temperatures=higher pressure. But the guage is in the same spot as usually (just below the half way point). I wonder if the coolant temperature sensor is going bad and causing the fans to kick in late.

 

BRILLIANT PINK!!! I took out the overflow tank and saw there was crap all over the bottom, so I cleaned it out and refilled it. Hooked it back up and went for a drive. When I got back I went ahead and WHILE LOOKING INTO THE TANK (i filled it up with water, so i could see clearly to the hole at the bottom) I released the pressure with that locking radiator cap and nothing but AIR came up through the bottom of the resevoir tank.

ALRIGHT!!! So at least now I know its not ubber coolant pressure causing the bulge. Its a massive build up of air in the system... BUT WHERE IS ALL THIS AIR COMING FROM??? I dont have a blown headgasket (my oil would be milky from the coolant if that were the case... and its very much caramelish)

Thanks for the input guys keep it coming, we're getting somewhere with this

 

Have you replaced your thermostat? I remember when I had my 3rd gen that my temp stat was starting to fail. The temp gauge would go up while in traffic but as soon as I drive it would drop down to normal. Than on a long drive the car felt like it was purging. Could never figure it out until my thermostat blew and coolant leaked all over the ground.

 

didnt i say that..

 

Speedracer- the thermostat is fine, its the same one I had on the 3.0. Its not leaking either.

gtr rider- jezz j00 did! I just didnt believe u :-X haha j/k lol

 

What im wondering is if the coolant passing through the 4G TB was like a suppression for the pressure of the coolant. I havent heard of anyone else having this kind of problem with the swap so its more than likely some other coolant leak somewhere.

 

The coolant going into the 4th gen TB shouldnt have anything to do with it. Im running a PF TB so there is no coolant hook up for that. IIRC that is just for cold starts or something.

 

Very true, in conjunction with the Fast idle cam. nvm

 

Yes sir. and I ran my 4th gen TB on the 3.0 for about 2 years with the coolant lines bypassed (I also canibalized that TB and took off the fast idle stuff, since there was no coolant goin to it, I figured it no longer served a purpose and took it off... no problems either).

Im doing the same now with my converted 3.5 TB. So that cant be a variable in this matter

 

I think that now you need to do the pressure test of the system. It is possible to have a leak in the head gasket that would allow the compression to leak by but not let the coolant go into the oil.

 

Yes sir... I just got back from hanging out with two nissan techs friends of mine and they both threw that in as a possibility FTL

Sigh.... I have the tester already, so I'll be testing compression this weekend and post up my results.... if it turns out there's a leak, i might as well get the dobuloz w/e ebay cams, since the cams have to come off in order to get the head bolts off. So hey it might just turn out for the better .... blah

 

ok, did compression test. its 210psi on all cylinders.

Here's the sweet part, 3 of the spark plugs (#3, #5 and #6) all had green deposits on them... gee I wonder what the one green fluid under the engine bay is? lol well BLAH, so now Im gonna tear this **** down to change the head gaskets.

Im going to use brand new OEM head bolts, 350Z triple layer HGs, and reuse the stock cams - not enough $ right now to buy the debuloz cams due to spring tuition coming up, so I'll pass on that.

So yup, that's the end of this thread. Thank you guys for the input once agian.

 

sheetttt, sucks mang... [ff]Now the mad scientists is going to have to rip apart the block...[/ff]

 

UPDATE- I have the Z33 HGs, and new OEM headbolts. Problem is Nismology has all the special t00lz I need to do the job, so until he gets done with his project...

I figured I had nothing to loose by closing up my radiator at the top... involves a BIG A$$ C-clamp. I figured either its gonna pop in a few days, or I'll crack it with this clamping, or I'll be able to close up the gap to buy me some time... well the last one was the outcome, lol.

 

ibducttapeftw

 

^^ Our engine is so small and cute without its heads lol

Down TO THE BLOCK BABY! With the engine in the car .... Now I have a problem, i have to figure out a way to remove the inner timing cover (angling the motor so it could clear the stud coming off the block) so I can re-do the silicone.

The pictures were taken with a cell phone 1.x MP camera, but anyways on the 2nd picture Im showing the bottom of my LH cylinder head. I know its not so clear but on Cyl #5 there was a crusty/sandy layer of something on the valves. I SUSPECT that to be coolant. On the RH head, ALL valves had it.

Another thing, is it normal for the intake valves to be so dark in color in contrast to the exhaust valves? Could the fact that I was running ubber 65-70 fuel pressure (POS FRP needs to go) have something to do with this?

Also, on the last picture, is it normal for the tops of the pistons to have a flaky coat of what seems to be carbon? I could literaly flake them off with my nail and pretty much scooped it with a light touch of a scraper. I suspect that this too might have had something to do with my ubber fuel pressure.

Thank you all, I am officially at the 50% mark.... and I have Saturday and Sunday to get this sucker running again. If I ask my old man to borrow his truck on Monday I might get decapitated FTL

 

Why didn't you pull the engine out of the car? I heard stories about trying to put on the timing cover and its going to be very difficult with the engine in. Good luck.

 

Well the outer cover wasnt a big deal with just angling the engine. The problem Im having with the inner timing cover is that i have the primary chain's rail/track w/e and the water pump sticking out drive into the inner fender before the cover is off the block's stud... by less than 1/2 inch. So I'll give that a try this morning now that the heads are off perhaps it gives me more room to angle around

 

Removal is the easy part. Installation of the outer cover is where it gets interesting. And like i said on the other forum, you should check the heads and block for flatness before reassembly.

 

Anyways since my last update this has happened...(i've had crazy work+this f'ing rain in Miami slowing me down, but here we go)....
-Cams are on and torqued down
-VCT solenoids are back on
-Coolant tube bet'n the 2 heads is back on
-Rear Timing Cover is back on
-Secondary chains are back on
-Primary chain is back on but Im trying still to take the slack out from bet'n the 2 heads and take it to the tensioner

Thats what it be about for now, werd

 

i'm having the same coolant problem as you but not as much pressure but I had this problem with my 3.0 thats why I put a 3.5 in but the problem is still there I replaced the radiator with a metal one (nothing was wrong with the one I took out ) it worked fine for a couple of hours then it started again.so I think that I have a restriction somewhere and I dont have any thermostat. So go figer I don't think both engines is bad.If you have any info to help me out I'll appreciate it. Oh my plugs are good no green residue.

 

Oh yea! forgot to update, Headgasket replacement was a success from what I could tell so far- compression test still pending. Timing chain did not jump teeth because engine is ubber smooth at any RPM.

Thank you guys for all the help, enjoy your holidays!