Cooling System Question

[silver7sport]

Good evening Team!

I recently purchased a 1995 525i and have a question. The car was parked for many years with unknown service history. Original owner passed and was left in garage over 10 years. I bought the car with 200k- non running.

First course of action was drop tank and replace fuel pump, plugs, oil change etc. I also elected to do complete cooling system update. Car ran great! I wanted to baseline everything due to unknown history. New radiator, water mump, hoses, thermostat.
I bled the system and ran the car for about an hour. Cap off and topped coolant off. When I put the radiator cap on and allowed the car to run at idle, I noticed a loose upper hose. Tightened and topped coolant again.

I used a block tester to look for any possible signs of bad head gasket. No color change.

What I have now is temp gauge stays dead center, heat works and coolant level stays solid at about an inch over the cold line when engine is running and up to temp. Sounds good so far right?

What I am concerned with is that the upper and lower hoses are hard as rocks. They are both hot but hard.

I have only driven the car in the neighborhood, BUT.... Should the hoses be hard? I don't see bubbles in cooling system. Just worried before I dump more money into the refurbishing. If I need to do head gasket..... I would do it now.

Anyone have thoughts/suggestions on any other way to verify we are in good shape?

[E34 Lives]

Sounds like you are on track with restoring this E34. Bleeding out the air in cooling system is key, thermostat has a hole on top that needs to be installed in the correct position to allow air to bleed and you should turn heater on to circulate out air in heater core. But I think your car is operating fine, with temp in the middle of gauge, this is good sign. The hoses should get hard when engine is up to operating temperature, and is normal. I would remove some coolant and not over fill, as you mention 1 inch above the fill line, it should be at the fill line, over filling can inhibit coolant circulation efficiency.

The CO2 blue liquid test results not turning green, is good sign that gasket and cylinder are holding, you can further test each cylinder with a compression test to further confirm health of engine and stick a scope in spark plug hole to see if there are any scoring and carbon build up.

Your next step is to make sure that you don’t have any vacuum leaks and start changing out all the fluids, power steering, brake, do engine flush and add additives (Liquid Moly) to your oil change. Replace brake lines and other components within braking system as they are pretty old and good safety measure. Valve cover gaskets, oil pan gasket. Rebuild suspension when funds are available.

These engines are very robust and bullet proof and can reach 300K miles and more. Happy wrenching!