Radiator hose blows off under boost? Why?

[r1jlewis]

Here is the issue, and it's strange. It's an S15 Sr20det, I put a Greddy head gasket on a couple of months back cause the stock one blew out. I have added a couple of things on it since then. Now I have a 25G top mount and raised the boost to 25psi. I had a ploblem with my stock radiator as it leaked out of the crimps, so i just put a Koyo in there. Now when I boosted it back then at 15psi, it would skwirt into the over flow at high rpm's then it would come splashinig out of the little pee hole in it. So in my infinate wisdom, I removed the over flow resevour and just piped it back into the water inlet into the motor. I took it up the street, reved it to full boost and the top of the radiator bubbeled up and blew off the radiator hose with the clamp on it. What the hell could be the problem??? How could the boost effect water pressure?
Modified by r1jlewis at 1:59 PM 5/14/2006

[boznuttz]

u need the overfill atnk, its there for a reason. the catch tank is there for when your system exeeds 15-18psi (radaitor cap bleeds off pressure). thats why it keeps blowing off. it really has nothing to do with boost. are you overheating at all? does the collant temp spike? more info guy!

btw why would u have an s15 motor? not worth the cash imo.

[r1jlewis]

Even with the resevour in there, it would shoot in there so hard that it would totally splash out of the air hole that's on it. It would take a lot more than 18psi to blow off the main radiator hose with the clamp on it, and also, the entire top of the Koyo in totally bubbled up and I can't even push it down. That has to be a crap load of pressure to make it do that. I did just look at the FSM and it suggeted that it's a head gasket problem, but it's brand new metal 1.2mm and torqued to spec. S15 cause it was new with low miles and liked the 6speed. Didn't want to rebuild an old one.

[xero1]

seems like you have a bloan head gasket. do a leak down test.

[Cyberkreig]

Yeah. it sounds like you might have compression leaking into the waterjacket. One easy check for this is to let the car idle with the radiator cap off. after a few minutes any air bubbles should disappare. if air bubbles persist or coolant sorta.. surges up and down thats a good indicator.

[karmakaze]

Yeah. it sounds like you might have compression leaking into the waterjacket. One easy check for this is to let the car idle with the radiator cap off. after a few minutes any air bubbles should disappare. if air bubbles persist or coolant sorta.. surges up and down thats a good indicator.

that is the only thing i could think of. for it to have built up that much presure you would have to be running really really hot and get there really really quickly. sounds like you will be pulling that head back off sometime in the near future.

removing the water catch was pretty retarded btw.

[Cyberkreig]

Sorry, i dont get the i'm with stupid. High radiator pressure and bubbles in the coolant are an old school mechanics trick to spot a hg problem. I dont pretend it is anywhere near as accurate as a leakdown, but it works.

[karmakaze]

Sorry, i dont get the i'm with stupid. High radiator pressure and bubbles in the coolant are an old school mechanics trick to spot a hg problem. I dont pretend it is anywhere near as accurate as a leakdown, but it works.

i was agreeing with you.

[Cyberkreig]

Ahh, my bad. I misunderstood, sorry!

[r1jlewis]

OK, got the head off last night and found a head gasket problem. Pictures show the black coating is blown off. Now, since it's a new greddy gasket and the metal still looks fine, can I just remove all the coating and reuse the gasket? Also, do you think this happened because I used the stock head bolts? I'm going to get the ARP's this time just to make sure, but the gasket looks fine, it's just that black coating that looks to be bad.And I changed the routing back to the resevour also.

[karmakaze]

OK, got the head off last night and found a head gasket problem. Pictures show the black coating is blown off. Now, since it's a new greddy gasket and the metal still looks fine, can I just remove all the coating and reuse the gasket? Also, do you think this happened because I used the stock head bolts? I'm going to get the ARP's this time just to make sure, but the gasket looks fine, it's just that black coating that looks to be bad.And I changed the routing back to the resevour also.

ummm, i have never seen a greddy HG in person, however, i am pretty sure that the black film is just the protective sticker that comes on pretty much any new metal to keep it from getting scratched up before install. your supposed to peel that off before you install it.

[ILikeMy240sx]

Clean up that gasket and coat the gasket with copper spray before you put it on. It should be fine.

Ive re-used my Apexi gasket about 5 times and each time I sprayed with copper spray and no prob so far... but then again its apexi.. hehe

[JesusLikesKFC]

while doing a hg in school almost did the same thing on a civic.... it happens lol.

[180fan]

bleh I had a greddy with no problems before and i've got no problems with my apexi gasket now either.

[r1jlewis]

Is if I clean it up and use the ARP head studs, do you think it will solve the problem? or should I get a different gasket? I really don't want to have to pull it apart again.

[karmakaze]

Is if I clean it up and use the ARP head studs, do you think it will solve the problem? or should I get a different gasket? I really don't want to have to pull it apart again.

you don't have to run ARP head studs. that has nothing to do with the problem. scrap of the black plastic off of the HG that you were supposed to remove before installing it, spray it with copper spray, and reinstall it and you should be fine.

[r1jlewis]

According to the manufacturer, the black coating is there for rust/dissimilar metal purposes and is not suppose to be removed before installation. Not a big deal with me to remove it and put the silicone spray on. Major question with me is why did it happen in the first place? Was it incorrect torque specs? What should the final torque be on the head bolts, also were do I purchase the copper spray?

[dustyk]

You said in the your post that your original gasket blew out. What was the reason for the stock headgasket blowing out? Did you overheat it etc?

Did you get your head checked and/or resurfaced after you blew your stock gasket? Id check your head for straightness before anything else.

[r1jlewis]

Never over heated it, just boosted it up to high from what I've been told. I did get it resurfaced and did a 3angle at the same time since it was off already, just to make sure. Even right now, overheating isn't a problem, but now I'm running about 25psi with a bigger turbo. I bought the copper spray just now, but am still a little skeptical since I'm running that much boost thru it. The FSM says to final torque at 26-32 ft-flb., should a go a little more to make sure?

[bardabe]

Never over heated it, just boosted it up to high from what I've been told. I did get it resurfaced and did a 3angle at the same time since it was off already, just to make sure. Even right now, overheating isn't a problem, but now I'm running about 25psi with a bigger turbo. I bought the copper spray just now, but am still a little skeptical since I'm running that much boost thru it. The FSM says to final torque at 26-32 ft-flb., should a go a little more to make sure?

that is the reason the head hgasket leaked down. the FSM I got says to do 26 - 32 - 0 - 36- 92 and then turn the bolts 90degrees. and after all bolts have been turned 90 degrees do an additional 90. (don't do the 180 all at once or u cna mess something up) trust me I rebuilt my own SR and I didn;t have a problem. I am actually on my 2nd rebuild with forged internals this time.

[karmakaze]

Never over heated it, just boosted it up to high from what I've been told. I did get it resurfaced and did a 3angle at the same time since it was off already, just to make sure. Even right now, overheating isn't a problem, but now I'm running about 25psi with a bigger turbo. I bought the copper spray just now, but am still a little skeptical since I'm running that much boost thru it. The FSM says to final torque at 26-32 ft-flb., should a go a little more to make sure?

ok i take back my previous statement. if your running that much boost you should probably have ARP studs. I don't think so anyway. is their anyway to tell? (my engine came with some aftermarket mods such as a 1.5mm head gasket and some sort of aftermarket pistons)

granted, I have boosted to 22psi and I don't have any problems and I don't have ARP studs. (once anyway, I don't plan to sustain that kind of boost until I get my oil cooler/filter relocation and oil pan installed)
Modified by karmakaze at 5:44 AM 5/9/2006

[Tj@TomsAutoPref]

sounds like a blown headgasket. or possibly installed backwards or upside down//

[spider_slayer]

that is the reason the head hgasket leaked down. the FSM I got says to do 26 - 32 - 0 - 36- 92 and then turn the bolts 90degrees. and after all bolts have been turned 90 degrees do an additional 90. (don't do the 180 all at once or u cna mess something up) trust me I rebuilt my own SR and I didn;t have a problem. I am actually on my 2nd rebuild with forged internals this time.

i'd much rather jsut buy a torque wrench.

anyway, i'm guessing that if the coolant systme is sealed the coolant is getting hot and expanding enough to blow the hose off. part of the resivors job is to collect the coolant.

if alot is spraying out when you are driving.....jsut don't put very much in...

[r1jlewis]

OK, I put the overflow hose back to original so it can flow out if need be. Bought a new cometic head gasket (which enjuku sold me an 88mm but my stock bore is 86mm and they said it's fine), ARP head studs, torqued to FSM specs but then did a final torque at 68flbs. Everything seemed to be fixed, no pressure in the radiator any more, no more spraying out water in the resevour. Cool!!!Now the new HUGE problem. After getting it all back together, running it around for a while, got the timing all set back up, she ran great and halling butt! So i took it to the track, ran it 4 times. First 3 ran fine (barked fourth gear), on the fourth run she made it almost all the way down the track then Bleweee. Radiator Fluid now in everyline there is, top of all pistons and in the bottom end!! How can i fix this one????

[bardabe]

OK, I put the overflow hose back to original so it can flow out if need be. Bought a new cometic head gasket (which enjuku sold me an 88mm but my stock bore is 86mm and they said it's fine), ARP head studs, torqued to FSM specs but then did a final torque at 68flbs. Everything seemed to be fixed, no pressure in the radiator any more, no more spraying out water in the resevour. Cool!!!Now the new HUGE problem. After getting it all back together, running it around for a while, got the timing all set back up, she ran great and halling butt! So i took it to the track, ran it 4 times. First 3 ran fine (barked fourth gear), on the fourth run she made it almost all the way down the track then Bleweee. Radiator Fluid now in everyline there is, top of all pistons and in the bottom end!! How can i fix this one????

From what I see in the pic you have 2 choises:

Choice A: find a block (I know someone selling one for 120$) and transfer everithing over

Choise B: New Motor.

you have a HUGE hole on the block that can't be honed or over bored sorry. and about the torque wrench you don't use it to turn it 90 degrees that is what the FSM says after tourquing to 92 ft/lbs you gotta do 90 more degrees 2 times.

-Juantons

[180fan]

you can also try to sleeve the bugger.

[r1jlewis]

If you can find me a block for the 120 and it's in good shape, email me at [email protected] and I'll send the money today. Let me know if it will fit all the S15 crap. Let me know ASAP. thanks for all the help...

[ca18det_boy]

just resleeve it.

[r1jlewis]

Yea, I got it to the machine shop right now and said they could fix it by a little welding touch up and resleving it. Guess I will go ahead and put a good set of rods and pistons in while it's apart. It's going to be close to 500hp and really don't want to have to break it all down again. Though I did have it on ebay for a couple of days, but then I settled back down and am fixing the bugger. There too much fun to sell it now, hell i'm already broke anyways!

[highmilehatch]

What are you using for engine management? Was the car even tuned for 25 psi or did you just "turn it up"? Did you reuse the stock headbolts?