Help with Wifes Van - Please

O.K., I'm at wits end and I need help. My wifes van is a 1999 GMC Safari 4.3 litre v-6. It has about 135,000 miles on it. The issue that I am having with it is that the crankcase will empty oil into the cooling system. Usually takes 300-600 miles. In diagnosing this, I have drained and flushed the cooling system and put a fresh oil change on it and 300-600 miles later, I have put three to four quarts of oil in the crankcase and the cooling system is full of oil.

Now, there is no water in the crankcase. The oil is as fresh as the day I put it in. It just seems to pump one way. I have been thinking blown head gasket, but then I read where the intake manifold gasket can go bad and cause something like this. The kicker here is, and whats blowing my mind is that there is no water in the crankcase.

Does anyone here have any experience with this kind of a problem? If so, PLEEEEEEEEEEEZE help me out. I have a friend who will help me work on it. I just don't want to chase one issue when it may be something else. Thanks.

Eric

Does it have a oil cooler in the radiator? (not trans cooler)if so it is proubably ruptured in radiator.Blown headgaskets,cracked heads and cracked block ,leaky intakes usually cause excessive smoking and crankcase filling with water not the reverse.

Larry Simpson wrote:Does it have a oil cooler in the radiator? (not trans cooler)if so it is proubably ruptured in radiator.Blown headgaskets,cracked heads and cracked block ,leaky intakes usually cause excessive smoking and crankcase filling with water not the reverse.

Apreciate the response. I am tending to think that the radiator is the issue. I have read elsewhere on the internet that a bad intake manifold gasket might cause this problem. I just want to hit it right the first time and don't want to start shooting in the dark replacing parts.

Your cooling system operates under pressure.Your crankcase does not.Your oil system is only under pressure in your bearing areas,an oil vein or in a cooler.

Larry Simpson wrote:Your cooling system operates under pressure.Your crankcase does not.Your oil system is only under pressure in your bearing areas,an oil vein or in a cooler.

Saying that the only place that oil will try to exit the system is in an oil vein or in a cooler, such as the radiator, correct?

Correct, those are the only places that the oil system would be operating under more pressure than the cooling system.I would pull radiator and take to rad shop,have them pressure check oil cooler coil in radiator that should tell the story.

Larry Simpson wrote:Correct, those are the only places that the oil system would be operating under more pressure than the cooling system.I would pull radiator and take to rad shop,have them pressure check oil cooler coil in radiator that should tell the story.

Let me ask you this, I can get a new Nissens radiator for around $130, shipping included. In your opinion, should I just replace the one that I have, or is there an option that a radiator shop can do that is less expensive?

Radiator shops can replace cooler coils but 130 for a new one sounds like more efficient investment.However I would make sure that was the problem before I bought anything. They also make external coolers where you could bypass radiator coil.You would also have to plug raditor coil fittings.

I've seen alot of GM vans with radiators mixing oil and water, but I've never heard of the coolant not ending up in the oil pan. Every time I've seen this, the dipstick comes up with what appears to be chocolate milk on it.

Also, the the 4.3 isn't nearly as intake leak prone as the 3.1, 3.4 and 3.8. Not to say that it's impossible, but I would consider the radiator to be your #1 suspect.

Larry Simpson wrote:Your cooling system operates under pressure.Your crankcase does not.Your oil system is only under pressure in your bearing areas,an oil vein or in a cooler.

Thats right , cooling system 11 to 15 psi ,, crank case vented 0 ,,, oil system 30 to 60 psi.

oil cooler in the radaitor has got to be the culprit no other place on the vehicle recives high pressure outside the engine other than the oil cooler housed inside the radaitor make sure your van did come with one im 99% sure it did mystery over,i know right at the holidays too ,install new radaitor also contanes tranny cooler.should be 4 meatal lines attached unless tranny cooler is in front of the radaitor all the luck in the world wish you well poppop

you could install a aux oil cooler if you perfer don,t get a nissan rad nothing fits lot of frustation aux coolers cheap usually easy remove grill remove oil coller lines run rubber replacement lines get too pipe plugs install the plugs in rad you will have small oil slick in rad flush soon hope this workes for you if you are running the orange or the new antifreeze remove it use the green this new antifreeze is no good google it my wifes saturn came with it i completly flushed the system reinstalled the green no trouble good luck i hush now again good luck poppop

Well, put in the Nissens radiator today. $125 delivered. Seemed to fit very well. My mechanic buddy told me that it looked good. He has to replace the heat sending unit tomorrow and then we'll see if this is the fix. I am seriously hoping that it is.

Going to ask him to hold onto the old radiator so I can dissect it and look at the oil cooler. It (the radiator) is the original and the van has 139,000 miles on it. Also, its paid for, so I have some scratch in the budget to have work done to it. I really like the van. Good get up n go and great hauler. thanks for all the help. Will update in a few weeks.

Eric

poppop wrote:you could install a aux oil cooler if you perfer don,t get a nissan rad nothing fits lot of frustation aux coolers cheap usually easy remove grill remove oil coller lines run rubber replacement lines get too pipe plugs install the plugs in rad you will have small oil slick in rad flush soon hope this workes for you if you are running the orange or the new antifreeze remove it use the green this new antifreeze is no good google it my wifes saturn came with it i completly flushed the system reinstalled the green no trouble good luck i hush now again good luck poppop

I cannot stress this enough. The GM Dexcool is really garbage. That stuff will clog your heater core and everything else. Get that stuff out of their ASAP, if you own any GM vehicle.

i never thought about a nissain radaitir in a cmc van nothing better than being thare best of luck poppop

Well, its been 4 days of driving with the new radiator and I don't see any oil in the system, praise God. Also had to replace a temp gauge sensor. Checked with an ohm meter and it was definitely bad. A new thermostat, 195 degrees, and good to go.

One unique thing, though (god I love old, high mileage vehicles! ) the temp gauge is steady at the 210 degree mark while driving. I can see the thermostat opening and closing, by the temp indicator rising and falling, but it still is reading about 15 degrees high. Now, I know that that is too hot, but I am putting more stock in the mechanical thermostat operating at the proper temperature than the electrical system of a ten year old 145,000 mile GMC van being 100% accurate. What I'm saying is, I believe that the engine is operating at the proper temp and the gauge is wrong.

Please share your thoughts.

Eric

Sounds right to me ,most vehicles with electronic guages read high from the factory,if you want more accurate readings you will have to go with manual guages.

I have an infrared temp gun at work that I am bringing home tomorrow and going to check the temp of the thremostat housing against the gauge reading. Hoping that the gauge is wrong.

I wouldn't put much stock in a factory gauge regardless, but 210 degrees is nothing to be concerned about. You can buy thermostats that don't even open until 210 degrees. The boiling point of water is 212 degrees farenheit, but antifreeze can go even hotter, and the fact that the system is pressurized, raises the boiling point higher still.

If you've ever been through the mountains with an accurate temperature gauge, the temperature changes that you see are pretty dramatic. With an old, overhead valve engine I wouldn't even raise an eyebrow until it hit 240 degrees. I know overhead cam engines are more vulnerable, but it sounds to me like you're well within the safe operating limits.

O.K., I just finished running the wifes van up to temp. The gauge reads 210 at idle. I put the infrared temp gun on the upper rad hose and housing and the highest that I can get is 150 - 160 degrees.

So, no oil in the coolant and the temp seems to be fine, I think that we can close the case on this repair. Thanks all of you for your advice and sugestions. They were all very helpful.

Eric