Oil bubbling on boost leak test.

[EagleTalonTim]

ok, I am new to the turbo world so I am going to have alot of questions. I have already searched this one and cannot find an answer.

I ran a boost leak test on my 93 talon and found that the system would not hold any pressure at all. I am not sure if I am doing something wrong or what. I used an air compressor and turned it down to 10psi. I used the design found here : http://www.vfaq.com/mods/ICtester.html Everything fit snug and I did not find any leaks that i could not fix except for the bubbling noise that sounded like it was coming from inside the head. It was not bubbling much. The car runs fine and does not miss. It is a little sluggish on take off, but i figure that is because it is an AWD automatic.

Another question....what is the BCS Restrictor?

 

[winterftbl]

The bcs is like a manuel boost controller in that it only lets you run about 10 psi. If you remove it you can get to around 12 psi. It should be located by your intake.

 

[TSG59_Steve]

Explain how you have the BLT hooked up.

 

[EagleTalonTim]

I just built it to the specs of the example, took off the intake hose, then put it on the intake side of the turbo and sealed it with the hose clamp. Is that right?

 

[EagleTalonTim]

anyone have any ideas? I need to get an idea on what to look for for tomorrow.

 

[perley03]

Explain how you have the BLT hooked up.

Well, my last BLT was not hooked up, but this is how I made it:
2 slices of bread
8 slices of crispy bacon
lettuce leaf
sliced tomatoes
mayo

Toast bread. Then spread on mayo. Add crispy bacon, lettuce, and tomato, cut in half, and enjoy.


Sorry, I could not resist when I saw the BLT. Plus its 3am and I have not gone to bed yet.

 

[EagleTalonTim]

. not quite what i was looking for. I am still left in the dark on what to do or what to look for.

 

[10's or bust]

my friend u're correct and yes it is a blown head gasket 4G63T are nortorious for them...The car runs fine b/c the gasket is leaking boost into the coolant side of the gasket seal meaning the car will run fine during most normal driving but will heat up quickly and in most cases overheat when pushing the car really hard or when car has to go into boost a sure sign of this type of failure would show up when u first start the car and its cold if it runs for two minutes and the radiator is already hot to the touch then the gasket is presurizing the coolant side of its seal...basically leakin combistion into the coolant passages..next time u test for boost leaks do it while the car is cold and check the upper raditor hose as it should have no pressure on it whille testing if it does then replace the head gasket..if all tests are negative and that's not the problem then u didn't seal up the tester properly and need to do so

 

[EagleTalonTim]

the head gasket is brand new and I torqued it down to 68 ft pounds. The head was just reworked after replacing 2 bent intake valves. The guy did say that when he milled the head, he had to shave 23,000's off. not sure if that is too much or what.

 

[EagleTalonTim]

one more thing.....when i bought the car, it had a busted radiator...i went the cheap route and bought one from a junk yard. the only thing is that the radiator is not as thick as the one i took off the car originally. I could not find one that was good that was that thick. When i do put my foot into it for a few seconds, the temp gauge goes up a little over half way. would that be from a blown head gasket, or because the radiator cannot keep up?

 

[95CarbonEclipse]

First off...

The bcs is like a manuel boost controller in that it only lets you run about 10 psi. If you remove it you can get to around 12 psi.

This is little misleading. You don't want to actually remove the BCS, you want to remove the restricter. The BCS restricter is a small 'reducer' inside the BCS inlet tube (the one that comes from the turbo/wastegate). To remove it, take a very small fine threaded screw and start to thread it into the restricter. Once you've got a good hold of it, pull it out. Now you should see about a 2 psi increase in boost pressure.

Secondly,

How many times have you tried to do a boost leak test? Sometimes when performing the test you're pistons aren't lined up quite correctly and there can be a small leak (simply turn the motor over once and retry) or you can pressurize your oil pan through the oil return line on your turbo. In order to make sure that this doesn't happen put your tester on the IC outlet pipe from the turbo (so that your pressurizing the IC pipe that leads to your IC then BOV, throttle body, etc.), this bypasses the turbo oil lines. Another way that you could hear bubbling possibly, is if you're pressurizing the the valve cover due to a bad PCV valve. To make sure that this doesn't happen during a test simply remove your oil cap. A good way to test your PCV is to disconnect it from the VC and pressurize your BL tester. If you hear air rushing out of the PCV, it's bad. Either replace with a OEM one (NOT, NOT, NOT Autozone, Pepboys, Schucks etc.) or get yourself a $2 check valve and install that inline from your IM to your PCV valve. If you're still hearing bubbling... you're f**ked. Just kidding... I just dont' know what else to tell you.

 

[EagleTalonTim]

i have done the test 3 times. all three times, i heard the bubbling. Each were after i drove the car for a few miles testing the temperature. I really hope it is not a cracked head or blown head gasket. the car does not smoke or run rough, but it does heat up pretty quick. The temp gauge sits right in the middle while driving normal, then goes up if i run it hard. I know this is a little high, but i figured it was because of the smaller radiator. What are some ways to check if the head is cracked or if the head gasket is blown? It still has good compression and there is no water in the oil.

 

[EagleTalonTim]

Is it safe to drive the car like it is? There are no signs of a blown head gasket or cracked head.....just the bubbling noise when i do a Boost leak test and the problem with it overheating when i drive it hard for a few seconds. Could that be since the radiator is smaller than the one that came out of it or is there really something wrong with the motor?

 

[95CarbonEclipse]

Again, try pressurizing after the turbo and see if you still get a bubbling oil sound.

 

[EagleTalonTim]

ok, i will do that when it stops raining. What would cause the car to run hot during normal driving and get hot fast when i drive it hard for only a few seconds? Is it because the radiator is too small?

 

[95CarbonEclipse]

I'm not entirely sure... but there are only so many things that go into a coolant system. I'd start with the most obvious, the t-stat. I once had one that was rusting out (don't ask) and would stick closed randomly. It would run hot for a bit and then go back down to normal operating temp. I wouldn't hesitate to just replace the thing seeing as how it's so simple and cheap to do.

Sidenote, if you've got a leak (whether it's a hole in your radiator or a blown head gasket) that coolant has got to be going somewhere, even if it's just to the atmosphere. The point is, you'll notice that your coolant level will be low. I'd assume that if your coolant level is good and you're not having to fill it up very often that your problem is something simple.

 

[EagleTalonTim]

When i put the head back on the motor, i put in a new thermostat. I did not see any leaks anywhere even with the engine running for 15 minutes or so. I have checked the oil and coolant to ensure neither have leaked into each other. So far so good. I may need to replace the radiator cap though. looks a little wore. Come to think about it....the reservoir did fill all the way up. It probably would help to get a new radiator cap. But, the question still remains.... if the cap was bad, would that cause the engine to get hot in a matter of seconds if i drive the car hard?

 

[Strm Trpr]

An old rad cap will definitely allow your temps to rise like they are.
It is supposed to hold pressure and not allow the coolant to boil.
As soon as the coolant starts to boil, you create steam in the system, and steam is much hotter and can collect in the head and cause hot spots.
If I were you, I'd still look for a replacement radiator as well.
I'd also have to advise not to drive the car until you get this sorted out, or you may be paying for your head to get serviced again.

If the bubbling sound you hear during your BLT is more like a glug glug glug, then chances are air is passing thru the turbo seal and into the center section and going down the oil return tube thus making the oil in the pan glug glug glug.

I bet if you put the tester on the input tube of the intercooler and test again, you won't hear any glug glug sound of bubbling oil.
Another thing to do is check out your PCV.
If it is faulty and stuck open it will allow boost to enter the valve cover instead of going into the engine, this will produce a sluggish feeling of a boost leak, and is a huge one at that.

Get some soapy water in a spray bottle and spray all hoses and clamped connections, bov, throttlebody elbow gaskets, throttlebody to intake manifold gasket, throttlebody springs to check in the TB shaft seals are leaking, intake manifold to head interface, and finally the injector seals.
A very common area for a boost leak on these cars are the injector seals that seal the injector to the head.
But since you just had your head redone, you probably swapped those out, but if not, get a new set of seals from the dealer, or from Fuel Injector Clinic, they sell new and improved Viton seals that handle the high engine bay heat from these cars better.

 

[95CarbonEclipse]

^^ This is almost identical to what I just posted 3 hours ago. That being said... I'd have to whole heartedly agree.