1967 1800S Oil in Radiator: Help Needed!
 

Hello All,

I recently joined the Volvo world when I purchased a 1967 1800S. The car runs, but is in need of some help and restoration. I have an issue I could use some help with: there is about 1 inch of clean oil floating on top of the coolant in the radiator. It is not creamy, but rather looks like someone just poured oil into the radiator. There is no water in the oil, however; nor is there any creamy oil in the crankcase vent tube/canister.Upon reading the original service manual for the car, I found a fault section under 'loss of coolant" which states "possible warn head gasket (oil in coolant)" But that's all it says. My B18B engine is also equipped with a stock oil cooler bolted to the block at the filter.

My question is if anyone knows what this is?My past experiences with blown head gaskets is that you find creamy oil in the engine (water getting into the oil) but I've yet to find clean oil in the radiator and no water in the oil. Does this happen with a blown head gasket on B18 engines, or does this sound like the oil cooler might have an interior leak which is forcing oil into the coolant? Any help would be greatly appreciated. Thanks!

Do a pressure test on the cooling system. Is there a transmission cooler on the radiator? It could be transmission and not motor. If the transmission lines (automatic trans) are connected to the radiator, disconnect them during the pressure test. You will know if the leak is there. Hope this helps.

I suspect that you have a manual transmission and that there is no transmission oil cooler function in your rad. I had the same oil cooler on my 61. It is used to exchange heat between the oil and the water and after all these years they tend to break down inside. As the oil runs at about 40 to 60 psi and the water only gets to 15 or so at the most, if there is a leak the oil will overpower the water. Best solution is to remove the old cooler, install a shorter nipple in the side of the block and screw the oil filter on there. You will need to use a later model lower rad hose, one without a section back to the cooler/heat exchanger, plus you will have to block off the pipe that goes to the top of the cooler from the side of the head (easy to make a steel blanking plate and bolt it on in place of the pipe). Did this years ago and no problems. With the new improved oils we have today, or even going synthetic, you really don't need that heat exchanger. At worst you might need to add a cooler if you are going to spend any time driving in 100F plus weather.

My 122 doesn't have an oil cooler or need one. they have the same engine pretty much, but maybe the 1800's had less room for the rad. I did have overheating issues and I took the rad apart and cleaned each tube out and soldered it back together. that cured any overheating issues.

you haven't had the oil checked at any gas stations lately have you? ;-)

I let the school mechanics change my oil. they instead drained the transmission pan and then put the bolt back so tight they stripped it out. then they pulled the pan off the tranny and I rethreaded it for a larger plug. .. then they wanted to wait for a gasket.. oh god I thought and these are our future mechanics. they got a quick and somewhat heated lesson on how to make a gasket ;-) at least i got my tranny oil changed