Hey guys, I have an issue with coolant lose. 2001 v6 140,xxx, stock

This car is not mine, but I do all the work on it. She is losing coolant, quite a bit a day, maybe a cup a day. There are not apparent leaks, it has not over heated, and no smell of coolant. Just recently changed the oil and the oil is ok, not milky. It does have a white milky substance that does get inside the oil cap. The plugs looked good, so really doubt it is a head gasket, it has and doesn't have all the signs. i have read about the intake gasket going bad, this is a possibilty, but how do you know for sure? The car drives and starts great, no missing or lack of power.

The other problem she is having is the coolant temp gauge wasnt working na dthe fan is always on along with a check engine light. i did change the coolant temp sensor and fixed the fan, light, and gauge. She drove about 15 miles and the gauge stopped working and fan kicked back on. Now her check engine light is back on as well. Im lost, any insight would be very helpful.

i am planning on a coolant flush and to pressure test it this weekend so hopefully get somewhere with the leak, but maybe someone that is always around this engine or has been around the block a few times with it can help me out. Thanks in advance.

 

First off Welcome to the forums.

Secondly what is the code that came up? Was it coolant related?

The secondary fan should not come on unless the engine gets really hot. There is one fan that should be on at all times this is normal.

As for the coolant leak I have a similar issue right now with my car. I have found no smell, no noticable leakes but loss of coolant. I have tracked my leak down to 2 places. The first is the O rings for the upper and lower intake the leakage there is more of a seapage and it evaporates before it hits the ground. The second place is where the head, intake and block all meet. This happened from me having to remove the lower intake after I had tightened it down once already when I put the engine together. I thought that the sealant was still good but I guess not. This is also the place were the intake manifold gasket will fail. You can put small amounts of water in the oil and not have the chocolate milk look since the water would evaporate quickly. That could also explain the milky looking stuff in the oil cap. Just a note though the engine can get some condensation in the block that can also leave that milky looking stuff on the oil cap.

Massey

 

Thanks massey, I figured the milky substance had to be condensation, its not a lot, but its good to finally know what it is. The code, not sure have not checked it, so that is in order for the weekend or Ill have her go to Vatozone to get a reading. The vehicle only has one fan, it may be two speeds but i know there is only one. It kicks on the minute you start the car whether it has been running all day or sitting all night.

Do the 3.8 have the elbow I have been reading about?
Should I start to think about doing the intake gasket?

Im going to honest, she has been very horrible about maintnance, I know when her water pump started to leak, she was losing coolant so she put some antifreeze in. Ended up being the opposite of what she really needed to put in, causing it to create all kind of havic with her cooling system. I tried to flush out the best I could, but it was pretty bad. Her car never overheated and always runs good, so I guess I'll have to see what the pressure test comes up with. Is it possible the plastic tank where the cap goes on to may be wittled down enough to cause a bad seal for the rad cap?

 

Sounds a lot like my 97 Buick LeSabre with the 3800 Series II. Persistent coolant loss without more severe symptoms.
For me the fix was doing the lower intake gaskets. Those spaghetti seals deteriorate and allow coolant ingestion.

 

Your pressure test should show you where its going. All the above are likely.

Right after I put my motor in I had the heat hose issue Massey mention but then I noticed I was putting a 2 pints of coolant everyday. I was looking everywhere for the leak. Dang thing was holding pressure. One day I got cause in a traffic jam for 4 hour and it was still took 2 pints. Then I forgot to add any and it sill took 2 pints. Turn out my over flow had a big crack in it and the hose to it was mostly pluged. I was driving 55 miles to work the 2 pints I was adding just got pushed into the overflow 10 min into the drive and by the time I got back home 110 mile later there was no sign of leakage.

 

Hmmm, never thought of that, ill look at that. Funny thing, I know the cap to the coolant res is non exsistant. ill have to let you guys know what the coolant test shows. Is there another sensor for the gauges or is it the same as the one for the comp, and which one controls the fan. Could all these problems be cause of the shortage of water as well. Most cars I have worked on still showed a reading even with the water not hitting the sensor.

 

Ok, the car held pressure at 16lbs, although it did have a small leak downwhere it may have moved a lb per 1 min. The rad cap did the exact same movement. I believe the leak down is from the tester itself(gotta love autozone rentals).

The cooling system was a mess yet again. I did a radiator flush again with running a cleaner through it as well. I think the losing of coolant was from the cap having gunk built up on it, first it wouldn't hold pressure at all, but after I cleaned it, it held very well.

Replaced the CTS again since the last one decided to stop working after a day, and the thermostat since this one was popped open. I guess we will have to see what happens after a week. It should be good, but thats what I thought a year ago when I flushed it and replaced most everything. Temp gauge works, cooling fan kicks on like its suppose to, car runs good. So lets hope this did the trick.

 

Next time use soapy water on the threaded joints on the pressurized tools. Sometimes they need tighened. I used teflon tape on every joint when I bought one.