Oil and Coolant leak of about 11/2 quarts coolant - 1/2 quart oil per night Leak 1 (Coolant) Appears to be coming from the radiator bottom right corner. Leak 2 (oil) Appears to be coming from the engine block or rubber blown gasket from under the block. I have checked the hoses and they are intact, as well as drainage plugs Any advice would be great!

Cracked head .check ur oil for a milky substance or check if there is oil in ur water

For there to be no oil on the transmission dip stick there must be a big leak in the box somewhere. Pouring in oil at one end will only be a waste of money until the leak is fixed. You will probably be looking at 1 1/2 gallons to fill the transmission. Check the coolant for oil in the water or get underneath and look for a large oil slick under the car.

If there is oil in water, then there may be a head gasket leak. However, half a quart of oil loss every 15,000 mi. is not bad. If van runs perfectly, then I wouldn't worry too much about it. Maybe try some Bar's Leaks Head Gasket Repair for $30 or so to fix the slow leak in the coolant system.

Check the bottom side of the water pump for wetness, as well as the lower radiator hose. The water pump if leaking, will run the coolant down the front of the motor,and can appear to be coming from the top of the oil pan. It is nearly impossible for the top of the oil pan to leak coolant.

SMOKE UNDER HOOD COULD BE COOLANT LEAK FROM RADIATOR ITSELF OR CHECK FOR LEAKING TOP RADIATOR HOSE AND CHECK FOR LEAKING BOTTOM RADIATOR HOSE.LOOK UNDER THE HOOD IF COOLANT BOILING OUT COOLANT OVERFLOW JUG ENGINE OVERHEATING FROM BAD THERMOSTAT OR BAD WATER PUMP.CHECK FOR COOLANT LEAK AT WATER PUMP WEEP HOLE.IF SO WATER PUMP NEED REPLACING.ADD MORE COOLANT UNTIL LEVEL CORRECT.TRY LOCATE LEAK. IF CAR OVERHEATED AND BOILED IT OUT. SMOKE UNDER THE HOOD CAN ALSO BE CAUSED BY LEAKING VALVE COVERS WHICH CAN BE FIRE HAZARD IF OIL LEAKS ON HOT EXHAUST MANIFOLD.

According to GM 1 quart per 1,500 miles is an acceptable oil consumption tolerance. 1 quart in 3k isn't bad.

I've had several gm 3.1 and 3.4 liters that have had there oil consumption issues remedied after the lower intake gaskets where replaced due to coolant leaking.

There are a couple of common problems that can cause oil consumption. Valve seals, bad rings, and PCV valves.

Valves seals would require a valve job which would requirethe removal of the heads. Rings would require a motor rebuild. Both of these are expensive options and oil is still pretty cheap.

Replacing the PCV valve might help. On the 3.8 it will be under the MAP sensor on the passenger side of the intake plenum.

As for as the intake gaskets, its a possibility but I don't have any hard evidence this could be the problem on a 3.8. Eventually the gaskets will start to leak oil. If you decide to replace them at that point I guess you will find out. I wouldn't do it on a hunch, its not a cheap repair.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

Hmm I don't recall 4.0 having oil coolers be way to be sure is to buy a coolant pressure tester fill the sytem (with water don't waste new coolant) and pressurize it. The most common coolant leaks on 4.0 engine that I see r from the rad and the water pump.

Normal oil consumption for a car is about 1 quart per 3,000miles. If you can calculate how much of a quart low you are per oil change you will be able to tell whether your oil consumption is excessive or not.

Heater core must be leaking. Turn it on defrost and see if the windshield fogs up.

Hi
No 1, replace the rad cap.
You also need to have the cooling system leak tested, for carbon monoxide ingress, the tester fluid will change color, indicating possible leaking head gasket.
The cooling system needs pressure testing, with a test pump.
This will normally show up a leak.
Check under carpets, for heater matrix leak.
Good Luck !

Don´t forget to give a fixYa rating Please !

John.