Second Opinion: Manifold Gasket?

Well guys, my vacation for the next two weeks is *off*. Looks like I will be trying to figure out the spontaneous leak that has erupted to dribble coolant on the ground right by my passenger side exhaust cross-pipe, blower box, and yes, some is even dripping off the passenger side mudflap! The crankcase is now overfilled by what appears to be half a pint, and the oil is turning dark. Gas mileage is in the flusher with all of this as well. Does this sound symptomatic of an intake manifold gasket problem or could I be looking at allthe wrong places?

She mildly overheated (Anything above 210 in my book is an overheat, hit about 225 degrees) when I pulled her into a parking slot at work. Got out there to the lot for lunchbreak to find the coolant recovery bottle completely empty and there was no visible fluid in the radiator filler neck. She took a gallon of premixed 50/50 Dexcool to top off between both the rad and the puke tank and on a lark, replaced the radiator cap.

Here's the confusing part - no smell of coolant in cabin or greasy,swirly marks on the windshield glass, but the scent of coolant is strong outside the truck. It was hot today, so natually the A/C was running which dumps a lot of fluid on the ground. After the top off and initial burping of the cooling system by idling for 15 minutes (In which many air bubbles can be seen moving in the tank) with the A/C off, there was still a growing pool of "fluid" where the A/C would normally drip fluid. I touched it....it was warm and oily to the touch and when sniffed - was raw coolant. So I really still have no clear idea where it is dripping from, but it seems to be landing on the exhaust on the passenger side, with the majority of it dribbling and pooling like A/C condensate (Or in the same vicinity) with some of it coming off the mud flap itself.

Before I go and hose my vacation funds away making a yacht payment on my mechanic's behalf, I figured I would run this flag up the pole and see whom has what to say. I do not plan on driving the truck another inch until I can book an appointent, so no worries about sludging the oil up just yet. Funny though, could it be because I am using a 10w-30 Shell Rotella HDEO that is has not turned into a milk-shake frothy brew? But I can certainly say that crankase oil level is elevated with the oil starting to turn a shade of "dark" from it's usually 5000+ mile honey brown. What do you all think?

This sounds like exactly what happened to mine. No coolant at the neck. Sucking too much from the resevoir. Then suddenly, big external leak in the lower manifold gasket. Dealer fixed for $600.

Look carefully around the gasket. Signs of leaking? Clean it first if necessary and then check again for seepage around the gasket area.

Check the water pump weephole. Of course check all hoses and connections. It'd be ashame to change the intake manifold gasket only to find that it's a loose hose clamp or something small like that.

Smell your oil dipstick. Do you smell coolant? (may not smell as strong if fluids are cold)



Well guys, my vacation for the next two weeks is *off*. Looks like I will be trying to figure out the spontaneous leak that has erupted to dribble coolant on the ground right by my passenger side exhaust cross-pipe, blower box, and yes, some is even dripping off the passenger side mudflap! The crankcase is now overfilled by what appears to be half a pint, and the oil is turning dark. Gas mileage is in the flusher with all of this as well. Does this sound symptomatic of an intake manifold gasket problem or could I be looking at allthe wrong places?

She mildly overheated (Anything above 210 in my book is an overheat, hit about 225 degrees) when I pulled her into a parking slot at work. Got out there to the lot for lunchbreak to find the coolant recovery bottle completely empty and there was no visible fluid in the radiator filler neck. She took a gallon of premixed 50/50 Dexcool to top off between both the rad and the puke tank and on a lark, replaced the radiator cap.

Here's the confusing part - no smell of coolant in cabin or greasy,swirly marks on the windshield glass, but the scent of coolant is strong outside the truck. It was hot today, so natually the A/C was running which dumps a lot of fluid on the ground. After the top off and initial burping of the cooling system by idling for 15 minutes (In which many air bubbles can be seen moving in the tank) with the A/C off, there was still a growing pool of "fluid" where the A/C would normally drip fluid. I touched it....it was warm and oily to the touch and when sniffed - was raw coolant. So I really still have no clear idea where it is dripping from, but it seems to be landing on the exhaust on the passenger side, with the majority of it dribbling and pooling like A/C condensate (Or in the same vicinity) with some of it coming off the mud flap itself.

Before I go and hose my vacation funds away making a yacht payment on my mechanic's behalf, I figured I would run this flag up the pole and see whom has what to say. I do not plan on driving the truck another inch until I can book an appointent, so no worries about sludging the oil up just yet. Funny though, could it be because I am using a 10w-30 Shell Rotella HDEO that is has not turned into a milk-shake frothy brew? But I can certainly say that crankase oil level is elevated with the oil starting to turn a shade of "dark" from it's usually 5000+ mile honey brown. What do you all think?

I just got back from looking at it after it has sat to cool. There is a definite line of what appears to be moisture around the lower plenum at the front. Hoses are good and tight, no leaks visible or felt around any hoses to the heater core, to and from radiator and pump. Pump is solid too. Popped the accessory belt off to check for bearing play or rough seals on the pump, she's good there. There is a small pool of fluid in the well just underneath the Linear EGR that was not present there before, soft, crufty crystals seen at various depths there too. On the ground, a warm pool of coolant that again, still seems to be leaking from the same area the A/C dumps water. I pulled the diptick again, not seeing any seperation of oil and coolant, it's a uniform gold-brown with a hint of sticky sweetness to it's scent. Usually, 1.5k miles into an oil change, it would only smell like....well, used oil. She's sucking the stuff up internally as well as dumping it at this point, with a seam of "wetness" all around the lower plenum sealing area on top of the engine block.

Update: Booked an appointment with a local ACE garage. Fellow I spoke to knew exactly what I was experiencing, and had figured into the price all of the extras needed to get the work done without me having to ask. Called high and low around town, not only did they have the best price/estimate, but use top-shelf parts and updated components/proceedures. Didn't even have to ask for an oil and filter change when it was done and tested against leak-down. :D I had to walk the other folks I called through the proceedure and the price went up-up-up with each reminder. This garage I am taking it to knew exactly what was entailed when I described the problem and actually instilled confidence in me, offered to take me back home and then pick me up when the work is done (Man, that's wild!) at 1/3 the cost of the other shop I usually play these guys off of. Nevermind the dealership. Talked to them at length about the problem and one of their garage technicians/mechanics - those clowns wanted $95/hr to just watch it drip in their driveway and over $1200 for the actual work to be done. I could have a new racing transmission for that kind of cash. Told them to pretty much do what my truck is doing now - sit and leak. :evillol:

Check the hoses going to the heater core.

Sounds like one of them has leaked.

Again, checked all hoses and clamps. Nothing leaking there, in fact all of the hoses except for one vacuum hose looks brand new. The old lady that owned the truck before myself did take care of it. It's leaking between the lower intake and the cylinder head on the passenger side of the block, dumping the fluid down in the same spot that the A/C dumps condensate, hence how it masqueraded for 2 days until the mild overheat when I pulled into work. A leaking heater core hose would be simpler to spot, and would not overfill the crankcase. Either way, it's being taken in for the updated gaskets, flush of coolant and oil and refill. Hopefully that will be the end of that. Thanks for the advice, however. :D

Followup: Just got my Blazer back! She's happy and purring like a kitten inthe shade on a hot summer day. Damn 'LT, I think your coffee drinking makes you psychic! What brand do you use anyway? But the long and short of it, in conjunction to having a bad lower intake seal, there was a heater hose leak. It was not visible, nor could be "felt" as I was feeling around blind after the engine was cool enough to touch. It did show up along with a spraying rear seal on the lower intake when the guys at the shop pumped up the cooling system to 15 pounds. Anyway, got out of there for a little over $300 which included all new gaskets, seals, coolant flush-n-refill, oil and filter change and heater hoses. I cannot stress enough, stopping the engine the moment I discovered the problem and refusing to drive it anywhere is what saved it. Coolant and oil mixing in the case ruins bearings fast. Here's hoping that everything will be okay, the guys at the shop said it looked damn good, but added a footnote to the bill. Yes, I know I have a vacuum leak in the dash that is not allowing the vents to pull cleanly open when runing in MAX A/C position. *snicker* That's a project for later on in the week.

Glad everything is working well for you.

Just remember, the vacuum leak in the dash will be seen by the engine as a vacuum leak just like any other seeing they all run off the same source.

Followup: Just got my Blazer back! She's happy and purring like a kitten inthe shade on a hot summer day. Damn 'LT, I think your coffee drinking makes you psychic! What brand do you use anyway? But the long and short of it, in conjunction to having a bad lower intake seal, there was a heater hose leak. It was not visible, nor could be "felt" as I was feeling around blind after the engine was cool enough to touch. It did show up along with a spraying rear seal on the lower intake when the guys at the shop pumped up the cooling system to 15 pounds. Anyway, got out of there for a little over $300 which included all new gaskets, seals, coolant flush-n-refill, oil and filter change and heater hoses. I cannot stress enough, stopping the engine the moment I discovered the problem and refusing to drive it anywhere is what saved it. Coolant and oil mixing in the case ruins bearings fast. Here's hoping that everything will be okay, the guys at the shop said it looked damn good, but added a footnote to the bill. Yes, I know I have a vacuum leak in the dash that is not allowing the vents to pull cleanly open when runing in MAX A/C position. *snicker* That's a project for later on in the week.

Excellent advice! Stop when you notice a problem! I keep repeating my same advice to everyone who has a coolant leak problem. Here it is again.

GO TO AUTOZONE AND BORROW THEIR PRESSURE PUMP, USUALLY FOR FREE. IT IS NOTHING MORE THAN A RADIATOR CAP WITH A SMALL TIRE PUMP AND PRESSURE GAGE ON IT. WHEN THE ENGINE IS TURNED OFF, COOL, AND FULL OF COOLANT, PUMP THE SYSTEM UP TO THE PRESSURE RATING OF THE ORIGINAL RADIATOR CAP AND START LOOKING FOR LEAKS.

BE SURE TO NOTE THE OIL LEVEL ON YOUR MOTOR OIL DIP STICK BEFORE AND AFTER YOU START. IF YOU SEE THE OIL LEVEL RISING, YOU HAVE AN INTERNAL LEAK.

If you have external leaks, they should be very visible and easy to spot.

Rick :2cents: