Greetings,

Thank you in advance for any support with solving this problem.

Here's the problem.

First, my 1988 Samurai Tintop started to overheat after a few miles of driving.  I flushed the radiator, replaced coolant, and it seemed to be working well.

A few months later, while driving (a few miles), the small 'L-shaped' tube under the thermostat housing and connected to the intake manifold ruptured/split and water was spraying out.  I believe it is a by-pass type for the coolant/water?  I also noticed what looks like oil (brownish-black) in my expansion tank - not much, but enough to be noticeable and make the tube in the expansion tank 'gummy' to the touch.

I did a temporary fix of the tube so that I could determine the cause/problem. 

I checked the thermostat - it's good.  I flushed the system again.  Water was draining fine and mostly clear from the bottom of the radiator.  I checked for coolant in my engine oil - looks clear.  With vehicle off, the radiator fan turns by hand, loosely, but not freely.  The belts appear to hold the correct tension.  The high and low tubes in/out of the radiator both become warm/hot after running the engine.

I'm still overheating within miles of driving.  The oil in the coolant is not much, but obviously not supposed to be there.

I believe I read that the intake manifold gasket may need replaced.  Any thoughts on this?  ...or any of this?

I appreciate the help.  I will post my progress and the solution too.

Thanks!

What are the symptoms that make you think it's overheating?

Also - find out where the oil is getting into the coolant - does the car have an automatic transmission - if it does one possible source is the transmission heat exchanger in the radiator bottom tank, a second possible source, especially given the "overheating" situation, would be a failed headgasket - I think  a leaking intake manifold gasket is more likely to allow coolant into the oil (via the cylinders) that oil into the coolant, but I could be wrong on that.

Perhaps a compression test might be a good place to start.

Thanks Fordem.

It's a manual shift vehicle.  I was thinking the same as you, but then I realized (read/learned) that manual vehicles don't have that transmission cooling component in radiator.

I'm thinking it's overheating because:
*First, the gauge it reading high.
*Then, if I keep driving it produces a small amount of white smoke or steam and makes a whining noise.  I believe the whining noise is coming from the small (finger size) tube that ruptured (temporarily bonded, but still leaking a little bit).

How can I be certain (or pinpoint) a failed headgasket?  The compression test?  I have an air compressor, but I'll likely need more tools/gauges to the compression test.  That's something I have never done.  Though, I'm willing to learn, and I'll look into that.

I do wonder why the small tube initially ruptured.  It didn't seem old, rigid, or worn. 

I'll keep pushing with it.   ...and I'll get back with any news.

Thanks!

A compression test, which, by the way, does not require a compressor, is perhaps the most common method used to diagnose engine condition, but the results won't necessarily indicate if the head gasket is leaking.

Compression tests are easy for most of us as they require minimal test equipment (just the compression test gauge, the car and a fully charged battery), but since you have an air compressor, a leakdown test might be more informative - do you have an autoparts chain nearby that rents tools?

The leakdown test set uses the air from the compressor and feeds a controlled amount of compressed air into the cylinders, one by one, through the spark plug hole, the gauges allow you to get a visual idea on how much air is leaking, and you can listen/observe to get an idea of where it's leaking - a hiss into the intake or exhaust would suggest the leak is past the valves, bubbles in the coolant could be a headgasket (or a cracked head/block) and so on.

Great!  I appreciate the information.  I have an auto store nearby that rents tools.  I'll likely do the leakdown test this weekend and post/share results by early next week. 

Thanks again.