coolant loss 1997 popular problem i guess

:confused: i am loosing coolant like crazy, doesnt show in the oil except maybe a little condensation on back of oil cap, none in the driveway, showing some signs of leaking around rad in the past (green stains on bottom rad hose and such) it leaks down like crazy under a press test, but no leaks found. rad cap didnt hold press so i replaced it. no different or maybe worse now. i have put in 2 gallons in a week of about 150 miles or so. i should see an external leak l ike this with no problem, is what i am thinking, right? other problems are map sensor code and hard to start like flooding. to start it i have to put my foot to the floor to clean out and then release and it will fire up slowly. seems to be excessive steam out the exhaust while warming up, but it doesnt smell sweet like antifreeze.
my thoughts are of course intake plenum problem, but its not showing up inthe oil. maybe lower intake gasket failure? if so how can i tell with out tearing down? ever heard of plenum leaking into throttle body? maybe bad throttle body? -continued-:confused:

:confused: i am loosing coolant like crazy, doesnt show in the oil except maybe a little condensation on back of oil cap, none in the driveway, showing some signs of leaking around rad in the past (green stains on bottom rad hose and such) it leaks down like crazy under a press test, but no leaks found. rad cap didnt hold press so i replaced it. no different or maybe worse now. i have put in 2 gallons in a week of about 150 miles or so. i should see an external leak l ike this with no problem, is what i am thinking, right? other problems are map sensor code and hard to start like flooding. to start it i have to put my foot to the floor to clean out and then release and it will fire up slowly. seems to be excessive steam out the exhaust while warming up, but it doesnt smell sweet like antifreeze.
my thoughts are of course intake plenum problem, but its not showing up inthe oil. maybe lower intake gasket failure? if so how can i tell with out tearing down? ever heard of plenum leaking into throttle body? maybe bad throttle body? -continued-:confused:

I love a challenge and working on cars, but right now i dont have the money to start trying things like a stab in the dark. this coolant loss is big and has potential to destroy this car so gotta find it. was thinking about tearing down and inspect plenum and replace lower intake gaskets. then if found plenum to be bad then go get the kit. btw i have had a lifter recently start to click or clang mor like it, in the morning. maybe related to coolant loss( washing that lifter out)?? this has got me worried and baffled, car has 130,000 and is in perfect shape other than this, HELP i will check this post regularly and will include any more info you guys or gals might need to help me diagnos this thing. btw love the car, but its soon on my black list,lol. thanks for reading or helping Joe

oops i kinda messed up that second post, what can i say i am a newbie,lol:grinyes:

You need to pull the upper intake off and inspect it around the egr stove pipe. My 1999 Lesabre went out at about 135k. here is no sealer that will fix this. If you let it go you can destroy the engine. I didn't touch the lower intake gaskets. My car runs fine now.

Ive seen plenums on ebay for cheap. I bought this one off the internet myself.

http://www.ineedparts.com/auto-parts/intake-manifolds/gm-intake-manifold-kit-17806.html

thanks for posting, did yours resemble same problem, coolant loss and none found externally? wonder why i am not showing ant in the oil, did yours show it inthe oil? thanks, joe

will be going out for a while, have to drive my gas guzzler quad cab, :frown: will check post when i come back

thanks for posting, did yours resemble same problem, coolant loss and none found externally? wonder why i am not showing ant in the oil, did yours show it inthe oil? thanks, joe

will be going out for a while, have to drive my gas guzzler quad cab, :frown: will check post when i come back

I assume you're filling the radiator to make sure it was full? If your pressure cap wasn't holding, you may have been boiling coolant out.

The description of a shakey start COULD be coolant on the plugs in some cylinders causing misfire at first. You should be getting coolant smell out of the exhaust pipe though.

You might pull the plugs to see what they look like. I believe coolant leaking in will cause a white deposit on the plugs.

Now that the pressure cap is working when parked hot check the elbows on the idler and other heater hose. Check the water pump weep hole with a light and mirror.

Check your water pump, I had the same problem.

I assume you're filling the radiator to make sure it was full? If your pressure cap wasn't holding, you may have been boiling coolant out.

The description of a shakey start COULD be coolant on the plugs in some cylinders causing misfire at first. You should be getting coolant smell out of the exhaust pipe though.

You might pull the plugs to see what they look like. I believe coolant leaking in will cause a white deposit on the plugs.

Now that the pressure cap is working when parked hot check the elbows on the idler and other heater hose. Check the water pump weep hole with a light and mirror.

what do you mean by checking elbows on the idler? that the little elbow on the water pump? where is the weep hole, i assume on the bottom of water pump?

Car does alot steaming out the exhaust when first started up, not matter what time of day it is, but it doesnt really smell like anitfreeze or wierd smelling like when you have head gasket leaking. smells somewhat "toxic" but not the same as i have smelled b4 with head gasket problem.

also, if water pump or hoses or nipple on water pump was the problem, wouldnt it show up with the pressure test?

im not questioning anyones thoughts just need to get to the bottom of this thing. thanks, joe

With your symptoms, I would bet you have a bad upper intake manifold (UIM). This is a very common problem on 95-98 VIN-K 3800's. The OEM factory EGR stovepipe is too close to the plastic passage in the UIM, so it eventually warps it due to heat causing an internal coolant leak. If you pull the spark plugs out of cylinders 5 and 6, I'll bet you'll have coolant in those cylinders (due to them being closest to the throttle body). Get this changed ASAP or you risk hydrolocking the engine or blowing a head gasket due to the coolant that's getting into the cylinders not being compressable.

ya i think i am going to tear it down and replace, wonder if i sould wrap the egr tube with header wrap to help with the heat or maybe heat shielded tape. will prolly go ahead and replace lim gasket while i am there due to little bit oil leaking from edges but not enough to smell or anything, well it might be the valve cover gaskets, huh? thanks all and will post how it goes,joe

Dorman makes an improved design aftermarket plenum (Part # 615-180) that comes with a new smaller diameter EGR stovepipe that addresses the issue so that won't be necessary. It also comes with the injector o-rings, gaskets, pcv valve, MAP sensor housing, pretty much everything needed in the box.

great, called advance auto and they have that dorman pn for 134.99

As far as your pressure test goes the answer is yes,I know from my 95 olds when we pressure tested it we heard a gurggling sound from the TB and then saw antifreeze coming out from it ,it also ran rough when first started which was the plugs being wet,I was lucky and caught it early.When you do the replacement do change the oil and filter and dont take a chance,Good Luck

thanks for posting, did yours resemble same problem, coolant loss and none found externally? wonder why i am not showing ant in the oil, did yours show it inthe oil? thanks, joe

will be going out for a while, have to drive my gas guzzler quad cab, :frown: will check post when i come back

Yes I was losing coolant with no sign of leakage on the ground

I pulled out my old EGR stove pipe with a hammer slide that you attach a vise grip on it from harbor freight. I used it once and returned it, heh.

whats the best way to reach the bottom nut on the throttle body, its right next to a support bracket and exhaust, thanks,Joe

The last time I did this in early September, I left the throttle body on the plenum until after I removed the plenum. Had to remove an angle support, or loosen the nut down below-I think to get the throttle body free it from the block. It was easier this way. I did one several years ago and had a hard time getting that nut off. Had to bend a wrench to fit in there.

yea I am also planning on replacing the UIM and noticed that bracket is going to cause a problem. Im thinking of drilling 2 holes in it and installing a small strip of steel and then cutting the bracket in two with my recrocating saw. Then use the bracket and 2 bolts to reattach. Sometimes its faster than fighting a bolt you cant reach.

R

looks like its problem just getting to the bottom bolt on the bracket to loosen, how fif ya do this,thanks joe

took it off, found no cracks in plenum, but found all kinds of fluid in valley area of the lower manifold, also found bolts for UIM all loose, like hand tight loose.

so water only runs through the end portion where the throttle body is, so where is all that fluid coming from

got it off, just pryed the bracket to the left and it loosened the bolt as well, look at my other post with pics of all parts involved,thanks joe

I posted a while back that some of the time the plenum is not the problem, it's the bad gasket GM used.
I was told "not true". Or was it, "I disagree"?
Chris.

possible, if i had more time and money i would just replace the gasket on this thing. cause not seeing plenum problem

I found the same on the one I did in early September. It had been replaced before, but I believe it was overtightened. The plenum only calls for something like 9 inch pounds-don't recall for sure, but it much pressure. It would be very easy to overtighten. I do not have an inch pound torque wrench. The gasket in mine was compressed and broken. The plenum looked good even where the stovepipe goes through. I went ahead and replaced it though since I had the new one.

Several years ago, I took one off our other Lesabre and it was burned/melted by the stovepipe. I used the epoxy Kenco kit on that one. It has not leaked and now has 204,000 on it.

I remove the ascrew and bend the bracket back just enough to clear it and pull the TB and UIM together. I clean up the throttle body on my work bench before re-installing it in on the new UIM
The wiring harness has clips (undo) by the EGR and evap solenoid that will give you enough slack to get it to slide out from underneath and to clear the stove pipe.
I re-install them together too by pushing the bracket back into position after setting the UIM/TB back on the engine and thread the bracket bolt first thing a couple turns then torque the UIM according to the pattern, then tighten the bracket
Hey that's just what works for me

so water only runs through the end portion where the throttle body is, so where is all that fluid coming from

Did you drain the coolant system before you pulled it?