Thread: Coolant sitting on top of lower intake manifold?

Hello, my wife has had this 05 GP w/ 3800 N/A since 06 w/ 13k mi. It now has between 160k and 170k. I have only had to do the water pump twice, coolant elbows twice, front struts, tensioner pulley bearing, serp. belt, plugs and wires, thermostat, and MAP sensor. It has also been Seafoamed a few times. I also flipped the motor mount dog bones. Last week I had to replace the rear calipers, pads, and rotors due to leaking where the e-brake attaches.

I had just done the second water pump and coolant flush (universal, not Dex) in the spring and since then it would have the occasional coolant smell when the engine is hot. I have also been noticing slight evidence of cross contamination in the coolant, but nothing bad so I have been monitoring it. It doesn't use any coolant, but has been using 1 qt. of oil every 3000 mi. since about 70k mi. She left today for the grocery store and I saw a new spot on the drive. When she got home I saw nice green coolant and some oil on the back side of the tranny pan and back side of the oil pan.

I then moved to under the hood to check on the water pump and coolant elbows and they look to be in good shape, but I found a pool of muddy oil and coolant sitting between two injectors on the back side of the motor on the pass. side. Just in that one pocket, and it looks like it spills out the back along the gap between the head and the valve cover and runs down. The source seems to be that bolt in there. I cleaned everything up and can't tell any better where the source is, but the bolt is tight and it doesn't seem to be coming down from the upper intake. The radiator and overflow res. definitely show evidence of cross contamination now, but nothing super alarming yet.



I don't understand what exactly failed to cause this, but I am assuming that I have lucked out and only need to replace the upper and lower intake manifold gaskets? I'm sure this is a pretty straight forward operation, but is there anything I should address while in there? Is there a good source for torque specs, or should I look for a factory service DVD on ebay? My buddy had issues with his intake gaskets on his 03 Malibu, but he ignored it and let the tank run dry, then drove it while overheating and paid to have new head gaskets put in along with new intake manifold, etc. About a week later the bottom end seized up from the coolant damaging the main bearings I assume. I don't want to go down the same route, doing the work myself or not. Any opinions on my new issue? Thanks guys!

its lim job time. thats the bolts seeping coolant.

when you put it back together, make sure to use thread sealant on the lim bolts.

Snug is the torque spec for the bolts.

Sometimes the bolts break when torqued back to factory specs.

make sure you buy the up graded metal lim gaskets. the upper gasket you maybe able to reuse. and a set of coolant elbows.

very common. a lim job is like maint around here when you first buy one of these cars.

your going this deep.



you want some permatex thread sealant. clean the bolts off well, then brush new sealant on the bolts.

you dont really need the rail off the lines, you can flip it off to the side, take the rail and injectors out as one unit.

the alt bracket, well you can see it bolted to the engine still. but you'll need a new upper coolant embow, note mine is broken, i snapped it, the took the lim off.

see the bolt holes in my pic there, they go right into the water jackets for the cooling system. so with out thread sealant they seep coolant. yours has been around for a while so its now leaking. i had like every bolt leaking on mine.

valve covers, buy felpro make sure they come with new grommets. they do leak when they go bad of course. if they are not leaking id leave them be.

the lim gaskets get felpro or acdelco.

heres a vid, its a super charged engine but pretty much the same job. this vid they also change the lifters, you just stop at the lim.

do this first, before the lim job.


how to flush coolant.


remove the t stat, put the t stat housing back on, take the upper hose off the radiator, then push it down to the ground to a bucket or let it fly.


get your garden hose out, put it in the rad turn it on, then fire up the car, let it run till clear water pumps out the top hose.


then turn the hose off, run the car till no more water comes out the upper hose. then turn it off. forget about the peck cock, they tend to break off.


put your t stat back in, with new gasket, the upper hose back on.





now take 1 gallon of full strength green antifreeze, not the 50/50 crap. ( parts store cheap green is fine to use) dump the whole gallon in the radiator, fire up the car, fill the rad with hose water till its full. top as needed till its ready to be bled of air. it will burp and take coolant as the water in the block warms up the t stat opens up for a few seconds till cold coolant hits it and it shuts again.


now to bleed the air out, let it idle rad cap off till the fans turn on, (when the fans are on the temp is over 195 deg, the t stat is wide open) then open the bleeder screw on top the t stat housing a few turns till a steady stream of coolant comes out the hole, shut the screw, top off the rad. cap it.


done.


the whole system holds about 3 gallons in total.

If you have a thermostat with the little air bypass valve on it, filling the system can be pretty easy. It allows air to move into the radiator as water fills up the engine.

You don't really have to flush the cooling system from lim gaskets going bad, but if you need to then do it. Removing the thermostat is the way to flush. You can put water in the radiator and let it flow into the engine and out the thermostat housing. This will flush coolant and most free particles. Not sure how much dish soap would work, Prestone makes a cleaner that can be added to your current coolant, driven for a few days, and then flushed.

if your doing a lim job and you've never flushed your coolant out to change it ( it dont last forever) follow the flush, add new coolant when done with the lim job.

also take some time a few days before the job to de grease your engine, who want to work on a dirty engine?

I like to flush before doing the work. Just saying

you dont have oil in the coolant, ( thats impossible to happen BTW) tap water is just fine.

thats dex sludge you see.

meh, been using nothing but tap water for like what? 25 years now? never had a issue.

if you want to pay for distilled water go right ahead. buy like 7 or 8 gallons, use 1/2 to flush with, the rest to re fill with new coolant.

Originally Posted by Jackal

I'm assuming I have both a LIM gasket failure AND a seeping bolt as it sure looks and feels like oil, but I could be wrong. I haven't run Dex in probably 7-8 years now. The pics and vids of the LIM gaskets showed oil/coolant sludge all over the gaskets and surrounding area, so I assumed.

Tap water contains a lot of solids that promote electrolysis in the event you have a ground issue, and if you do it deposits in the radiator...I just don't do it, but to each his own.

Only way oil can get in the radiator, is if the transmission cooler leaks internally. If it's brown, it's sludge from dex cool and should use prestone cleaner like I mentioned earlier. This is what I did on our impala. Ran straight water and cleaner for a week (in warmer temperatures) Add it to the current coolant if it ever gets down to freezing. Then flush with water.

+1 on cleaning the the engine before working on it. Before I did the lim gaskets on our impala, it was a horrible mess of oil and coolant, and dirt. I sprayed it down with degreaser and let it sit, and used the powerwasher on half power and sprayed it all down, just avoiding direct contact with the alternator. You can get them wet though. Heck my friends aurora's alternator is at the very bottom of the belt system, and he drove through some 2 feet deep water and it's fine. It had to have been completely submerged in water, and spinning/charging at the same time. Still works.

All tap water is different in different areas, personally if it bothered me I would flush with the garden hose, but run a few gallons of distilled through the system before refilling just to flush the straight tap water out. Like I mentioned, taking out the thermostat is the only way to flush. If you didn;t remove it, all you did was drain and refill. Which gets very few of the sludge and contaminants out of the coolant. You have to run water through the block and radiator, which will carry loose particles out. Also you must flush in the reverse direction for heat exchangers such as the radiator and heater core.

What do you mean that the thermostat housing doesnt look like it will seal very well? You will have to clean any corrosion off the housing and lim before reinstalling with a new gasket. I use a razor scraper blade on the housing personally. Works really good if you're careful with the soft aluminum. Also, when flushing, you don't have to reinstall the housing without a thermostat, leave it all off completely.

Let's think about the oil and coolant systems to better understand why some are saying you shouldn't have engine oil in the radiator.

Coolant system is under 13-16 psi all the time. The oil going through the head and lifter valley isn't pressurized, it's returning to the oil pan after being pumped around the engine. Oil will wick up the LIM bolts and get on top, however if you find a mix of oil and coolant it is very likely you also have a valve cover leak.