(89)driving on highway temp high 284*f then drop to 180* settle at 220* .. this cooling system is **%$ me off...what is wrong now? i took reading with my electronic temp gauge temp is at 195 -210*f when running..also i am using felpro 1010 heads gasket, and 1204 on intake flow flow through intake

i think its the coolant switch..

i have , clean and flush rad, installed new gasket(rebuild), new cap, new wter pump and hose through,burp system ( i dont' know how many time now)..did pressure test on system ( held @ 17lbs for 30minutes, which i am told is good, on warm engine),

there is no coolant in oil, no white steam out of exhaust, no oil in coolant.on two ocassion the over flow tank, overflowed, i had distilled water with green coolant. it seems to foam up. i have changed it as well to plain water untill i can resolve this issue.

 

It sounds like bad gauge wiring. Maybe the sending unit. Sub in a mechanical gauge, temporally, to see if it agrees with the dash gauge.

RACE ON!!!

 

Something for you to check.
I had a problem like this leaves and junk that you can not see get stuck between the rad and the condenser and move around and give the high coolant readings, and another thing to check is the coolant sencer wire sometimes it get's to close to the exhaust manifold and grounds out and that gave me over heat, when the engine was normal.

PS pulling the rad is required to get to the junk that get's stuck but it's not all that hard.

Ken-can

 

your're kidding rite?

 

well i did leak down test again! I suspected # 8 , on tdc i hooked up my gadget and put 80lbs air into cylinder. the &()(&(^% rad started bubbling then the air bubbles.
well seening that ther are new gaskets. i suspect the heads may have developed/or had a crack. Now these heads were supposely checked twice( had to take them back twice for other problems but were never pressure tested for a cracks). is it possible for them to be cracked though an exhaust port water jacket side? what do you think CFI-EFI?

 

any opions??

 

Man, i hope it ain't the heads

 

Probably. Why just the exhaust port? When you pressurized the cylinder, both valves were closed. A leakage to or from a port wouldn't have caused bubbles in the radiator. Were the heads surfaced or checked for flatness when they were at the shop? Did you check the deck of the block for true and flat when the heads were off?

RACE ON!!!

 

new felpro 1010 head gaskets, and intake 1204..the block was deck .020", heads were .005 (when i took them back a second time, they did not do pressure test on heads, visual only)..Could there be a internal crack ? one that can not be seen?..before rip and tear thing apart again, .. maybe intake gasket? i would like your opinon

the reason i ask is, none of the other cylinders allowed passage to coolant..i have removed all spark plugs to analyse a "WASH OUT" condition , but there are all the same color ....check to see if water leak into # 8 this morning.. No water visable. when i applied air pressure with a stethoscope i could diffentlly hear bubbles at the temp switch and around the intake. this afternoon i puled vavle covers. checkd torgue HEAD bolt 67 lbs short bolt a few less 63lbs..
should i retorgue?

 

opinon please..^^^..

could wait i added more torgue no change air stll escapping! Pi$$ing me off...

 

It isn't an intake gasket. Re-read my last post about the valves being closed and no pressure in the ports. From all your description, it has all the ear marks of a cracked head. Especially with the freshly surfaced deck and heads. It would pay to double check them, however. Before you yank it all apart, you might try re-torquing ALL the head bolts in the proper sequence. If you had to go another 5-10 ft.lbs. higher, it wouldn't hurt anything. At this point, what do you have to lose? Who knows, you might get lucky. But it really does sound like a cracked head. If the shop can't pressure test them, have them Zygloed. If they can't do either, find a new shop. The good news, is that aluminum heads are more readily repaired than cast iron.

RACE ON!!!

 

while i was waiting i did retorque (Added 10lbs)heads. ther is no change...i guess it tear down..reinspect.. i have die pen testing equipment here, Should have done that before installation, i left that to head rebuilders.. damn ..hindsight .oh well back to tear down.

if they are cracked at least i can reweld them right here in shop..

thaks for your valued opinon

 

Let's brain-storm this.

If you pressurized the cylinder and air bubbles showed up in the radiator, so somehow the pressurized air is getting from the cylinder to the coolant system.

By process of elimination is has to be:

the block
the head gasket
the head
the intake gasket
the intake

Question then becomes, which is it?

You pressurized the cooling system with 17 psi, but you put 80 psi on the cylinder. That difference in pressure could account for the coolant system pressure check to pass, while the cylinder pressure check to fail. 17 wasn't enough but 80 was.

Was the intake manifold cut too? (Since you had the block decked .020 and the heads .005)

If you used a dual gauge leak-down tester, what was the percentage of leakage?

How did you orient the head gaskets when you installed them on the block? "O" ring up or "O" ring down?

Do you know how smooth the block deck and head surfaces were after the decking? Too smooth a surface can cause gaskets not to seal.

Jake

 

Jake,
How do you get the intake manifold or intake manifold gasket? I don't deny the possibility that they are leaking, too, but how does a pressurized cylinder cause bubbles in the radiator, through the intake tract? In order to pressurize the cylinder, both valves have to be closed. The way *I* see it, that leaves the intake manifold and gaskets unpressurized. Therefore, I don't understand how a "fault" in the intake system is going to cause bubbles in the cooling system. Help, please.

RACE ON!!!

 

The way I approach a problem like this is not to assume that something's "right" or sealing properly. At the start, everything's on the table. Once I identify the possible causes, everything I identified becomes suspect.

One of the oldest ways to detect a leaking head gasket is air bubbles in the coolant at the radiator.

Compression pressure can enter the coolant system in different ways. Pressure in the cooling system is limited by the cap being used, yet the compression pressure is many times that amount; guess which one's gonna win.

First, I'm not prepared to assume that the valve(s) are sealed tight.

If they aren't, and the intake manifold gasket is sealed solid to the intake, but leaking, even a little bit on the head side of the gasket, the pressure can migrate under the gasket to the next weakest point, sort of like water seeking it's own level or the weakest link in the chain. Same thing applies to the other side of the intake gasket, the intake side.

Remember, my thinking is that 17 wasn't enough but 80 was. So even though the pressure test at the radiator, (using17 #) wasn't enough to cause the leak to show up, when confronted with 80, it could be a different story.

Same thing applies with the head gasket. It, too, can leak on both or either side. Even a valve can leak pressure if it wasn't lapped in properly, so they remain suspect.

I also suspect a machining error if the gasket surfaces on the block and/or heads were ground too smooth. You should be able to catch your fingernail on the surfaces when properly done. Machinist have their own language, and my vocabulary isn't up to speed with their surface roughtness lingo. I think you get what I mean though.

What I try to do is examine ALL the possibilities and eliminate them one by one until the source is found. Kinda like throwing a wide loop, as we folks in Texas say. Fishermen probably say something like 'cast a wide net'.

Anyway, that's my thinking.

Jake

 

Another few points to consider:

With using a compression tester, it'll hold the highest pressure attained, but a leak-down tester works differently.

When you pump up a cylinder with pressure, using a leak-down tester, it doesn't hold that pressure unless the compressor continues to compensate for the leakage by adding more compressed air. There will always be a certain amount of leakage, normally only pass the rings.

In a well sealed up engine, you'll still have leakage past the rings though; it's the amount that's important to note.

Somewhere in the neighborhood of 6% or less is about the average leakage with normal ring gaps of about .018/,020. Total Seals can reduce that more.

Sure you can run with more than that, but power suffers the greater the leakage; blow-by increases too. But if you're getting leakage well above 10% on a fresh engine and the rings have had time to seat, then you can bet something"s wrong.

That's why I asked what the percentage of leakage was. If it's way up there, I'd be hard pressed to put it all off on ring leakage. Instead, I'd be looking at everthing ABOVE the piston.

Just trying to help.

Jake

 

I agree with all that, above, with the exception of the intake tract. First, I'm not saying it doesn't have any leaks. But I AM saying that the pressurized cylinder isn't leaking 17# + pressure into the intake system where it could be the cause of the cooling system bubbles. If he opened the intake valve and applied 80# pressure to the spark plug hole, he couldn't pressurize the intake to 17 pounds. The minimum air throttle opening, alone wouldn't allow that kind of a pressure build up. I'm sorry but I believe you are wrong about the cylinder pressure test indicating the intake tract as a possibility. Again, I'm not saying it can't be leaking, I'm saying that, that particular conclusion can't be drawn from the that test.

RACE ON!!!

 

to add
1) 17 lbs test to coolant system, held for thirty minutes, pressure declined as temp dropped, taken @ 170* F finale Temp 140*f
2) 100psi into cylinder #8, valve closed, bubbles in rad.
3) 100psi into all other cylinders vavles closed. no bubbles
4) compression test @ 175lbs/ per cylinder..
5) leak down test pressure valve closed 100 psi applied . revealed constant presure decline slowwly but at steady rate except for cylinder number #8 . pressure dropped quickly. noted* air bubble in rad.
6) button everything back up, run to op temp. air bubbles in rad
7) observation: no oil in coolant. no coolant in oil, at op temp coolant release into over flow. @ room temp coolant siphon into rad leaving overflow tank empty, start engine coolant light(new) comes on. check coolant, adding to top up. drive car, coolant fills overflow, causing over flow. ( drove by chev dealer seen new C6. reminded me to fix old car)

what was done :
1) block decked .020".. machine finish was as jake described, not to course but enough to drag a nail.
2) heads planed .005" machine finish a bit smoother, ( good in my opion)
I did have to take heads back for other problems unrelated to surface.
3)felpro 1010 heads gaskets, intake gasket 1204. with this combination, i was lead to believe that cooling is more effective. ( i see the difference in gaskets and can see this happening)
4) retorgue heads to 70ftlbs and short bolts to 65ftlbs . retest #8 ..no change still leaking air into rad
5) i did check intake to block fit before finale assemble. both surfaces mated properly, i used plasta guage to determine fit

what was not done;
1) heads were not pressure tested as to my requested. an assumption was made here. one head #8 leaked on the first reinstall. ( not surfaced at this point)
2) at this point. a block leak test could be applied to determine if exhaust gases are present in coolant system. but really think this is not needed.

CFI_EFI ???would that be the same as DYE PENTERATION TEST? i use this method of testing to determine surface defects in stainless steel.

 

I am not familiar with the "DYE PENTERATION TEST". Check the literature to see if it's effective with aluminum. You have been quite thorough, and this explanation details your testing very nicely. Again, I see no way that the bubbling radiator indicates a problem outside of the cylinder. That is not to say there can't be other problems, but *I* don't think anything you've done, so far, indicates that. In my mind, the prime suspects are the head gasket, the head, and the block. The first thing you will have to do is pull the head. That will give you the opportunity to inspect the head gasket for signs of leakage. Assuming the gasket is OK, testing the head is next. Even if you find fault with the gasket, checking the head for a leak, and true and flat, AGAIN, is a good idea. If both the gasket and the head check out, things start to get REAL serious. I doubt I've said anything, here, that you haven't come to realize. I hope it's the head gasket. I have my fingers crossed for you.

RACE ON!!!

 

..going to remove head do checking again...
starting right away .. it should be off in about 1.5 hours..
i'll let know what happens...

thank again for the info.. i appreciated it !