I went to the drag strip on Friday night after some tuning on Thursday. The car ran pretty good before the track. Its a 99 Si with poor man's type R (12:1 CR).

I get there and make my first pass, I have some traction issues but I trap 4mph faster than I have in the past. So I'm like cool, the car definately feels a lot better. I make my second run, I bog, and the car doesn't pick up as well as it did the first run or earlier in the day. I run 4mph slower than the first run. I go back to the pits and notice some coolant on top of my radiator fan. I've had some leaking issues with the resavoir line in the past, so I just tighted it up a bit. I figure the loss of MPH was due to the bogging. So I make another pass, the far feels like VTEC is engaging and disengaging randomly. I've had issues with my OBD2-OBD1 conversion harness before as well, but I thought I got everything fixed with it.

My oil pressure is good, temp is average, and my oil level is fine. I check everything, fine. So I make another run, slower than before. I pop the radiator cap off and start the car. It takes a few seconds and it starts bubbling consistantly, its never done this is in the past. The car isn't smoking and isn't overheating, but its running a tiny bit warmer than usual (I'm also running a new PWR radiator/cap). I suspect a headgasket, even though my compression numbers are still consistant with my old numbers (240-250). Head was milled and block was decked. This motor only has 2200 miles on it so far. I will try to check my oil to see if it looks funny and try to get access to a leakdown. Anyone have any input? I don't know if its multiple problems or what....

 

bump

 

My car bubbles slightly, I actually can't tell if its bubbling or cause by the vibration my engine creates. My car operates normal, temperature is perfect and compression numbers are great and no oil in my coolant or vice versa. So in my case its nothing to worry about. Same goes for you maybe, there is a way to see if its serious though. Stick the over flow tube in some water while the engine is running, if it bubbles then its your head gasket. Also whens the last time you bled the system, you can try that and see if that helps.

 

"if it bubbles then its your head gasket."
thats what i have been told

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eflove &raquo;</TD></TR><TR><TD CLASS="quote"> "if it bubbles then its your head gasket."
thats what i have been told</TD></TR></TABLE>

Thats not always the case, so that theory is wrong.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 90blackcrx &raquo;</TD></TR><TR><TD CLASS="quote">

Thats not always the case, so that theory is wrong.</TD></TR></TABLE>

what else would make the coolant bubble? assuming the system was properly bled free of air.

 

head gaskey

 

Yeah, I'm really starting to think its a head gasket. The car hasn't overheated, but its been running warmer than usually (about 5-10 degrees according to my autometer water temp gauge). Its also been squirting onto the top of my radiator fan from somewhere, not sure if its from the cap or the resavoir tube.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jweller &raquo;</TD></TR><TR><TD CLASS="quote">

what else would make the coolant bubble? assuming the system was properly bled free of air.</TD></TR></TABLE>

Well one could be air in the system, another possibility that could fix it is changing to a lower temperature thermostat. I'm not saying its not the head gasket, but there are other things it could always be.

 

I'm in the same situation, little tiny bubbles at idle when I bleed it.

It could be that the head is lifting, but I checked the torque on the arp studs and that was fine.

It could be the headgasket, I got a leakdown test done and it came out perfect.

I got a 1.3 bar radiator cap, and all that did was make so that I didn't spill so much coolant into the overflow tank.

So im at a loss at what it might be.

 

I just did a leakdown and it was normal as well. No bubbles into the radiator. It only bubbles after the car has warmed up. I also noticed some oil in the coolant as well. Its floating to the top when its starts to bubble. I'm thinking there is a leak between the oil galley and coolant jacket. SO I am going to try to torque down the head some more tomorrow. I've heard from some engine builders that ARP bolts need torque more than what they say. I guess I'll find out tomorrow.

 

yea its true, torque them to 80 ft lbs

they say 65 but thats not enough, especially for my motor.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jweller &raquo;</TD></TR><TR><TD CLASS="quote">

what else would make the coolant bubble? assuming the system was properly bled free of air.</TD></TR></TABLE>

cracked water pump, but that would be leaking externally too, or maybe not? depends. Ive seen some weird **** lately.(with volkwagens that is) But yeah I would go with the head gasket for my bet. I would check the cooling system for leaks by pressurizing it with a special tool. (Not sure exactly where you can get it for cheap?) snap-on, mac??

 

Well, I've talked to a few mechanics and they have all said that if its already leaking, its too late. So off with the head today and hopefully a new gasket fixes all.

 

lemme know how it turns out, I'm still skeptical b/c the leakdown came out fine, but who knows.

 

A leak down tests only tests the cylinder heads ability to seal properly (valves and cylinder head integrity.)


Modified by mntuner2 at 3:53 AM 8/27/2003

 

it would also show a leak in the headgasket, b/c the air would escape through that passage.

What could be happening is the head might lift a little under boost, but like I said I torqued them again.

The leak may also be present when the cylinder pressure it at its peak (full boost)

 

What passage is that? Last time i checked when the leak down test failed you either had a malfunctioning valve or a cracked head. The headgasket is downstream of the head so you are wrong. Now if you are talking about a compression test, yes the faulty head gasket would show up on the compression test.

 

wtf are you talking about.

the compression tester and a leakdown tester are tested the same way.

They both screw into the spark plug hole, I think you need to learn the difference between the two before you someone.

only difference is the leakdown tester uses compressed air to find the leaks, while a compression tester uses the cranking of the engine.

go read up a little bit bro.

a leakdown tester is WAY more accurate in finding and leaks in the combustion chamber.

heres a couple for ya

 

A leakdown CAN tell you if you have a faulty headgasket only if the fault is between the cylinders or between the waterjacket and the cylinder.

I just got back from changing it, I am not completely sure if its fixed or not. The coolant had to be bled and there was probably still some air in it. I won't know until tomorrow.

 

ok cool, did you check the torque on your head bolts/studs?

mine were ok, but never know the head still could be lifting. on mine anyways.

might just have to try a new gasket and see.

 

The studs were off a by about 5 ft-lbs on 2 of the studs, so that may be a small reason. But just out of curiousity, I went to check it right now. It seems as though it (bubbling) doesn't do it as much, but it still does it some. I am wondering if my mix is not lowering the boiling point of water enough. I probably barely have 10% coolant. I wonder if a higher concentration of coolant would stop it. Well, I might have just wasted 4 hours...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 90blackcrx &raquo;</TD></TR><TR><TD CLASS="quote">
Thats not always the case, so that theory is wrong.</TD></TR></TABLE>

Ditto, I changed out a radiator and solved this problem before.

 

I think you are talking about a cylinder pressure differential test not a leak down test. Don't get pissed if you are not sure what you are talking about. Oh yeah, are you a ASE master mechanic? Cause I am.

Just for ***** and giggles, right back at ya dummy

This is my last post here cause obviously we are on seperate technical levels.

 

a bad headgasket will cause the coolant to bubble. Because of compressed air leaking out and into the coolant.