87 300SDL no heat, and also engine never warms up
 

So, i have almost no heat in my 87 300SDL. The engine never warms up to 80c. it get to about 50 to 60. I am guessing it might be a thermostat issue. It also only blows up to the windshield, and never blows any air below towards the feet, so the feet are always freezing. now sure if these problems are connected or separate. My guess is if it is seperate the thermostat is bad, and the flaps might not be opening. Any ideas?

You are right about the thermostat. It is the one on the engine block where the radiator hose is connected and that controls the coolant flowing through the radiator. It is stuck open and the car never warms up.

your car is also Suffering a vac leaks at the climate control pods, or you have a big enough leak someplace that they dont have enough oomph to work right. my car has the same problem at the moment

Could have no thermostat, mine was without one when purchased. Overheat in summer, too cool in winter.

Do check the monovalve solenoid's diaphragm for a tear, this typically causes loss of heat when vehicle is in motion. They are $50 or less to fix, and simple. Maybe five minutes.

Your lack of heat to your feet is due to the leaks in the HVAC, most likely the three pods behind the glove box area. Buy a MityVac to test properly. Pull a vacuum on them to test. Figure around $175-200 for the parts and about an hour to install if your first time. I can do them now in 20 minutes at the most. :) ... this also plays with your A/C come the summer.

I will go ahead and replace the thermostat. But not sure what all the stuff is about the HVAC system. What is the monovalve soleniod? and how do i check this? I will also look for any vac leaks as well.

1147213007 should be the PN, near battery with the four phillips screws atop.

Will not really be able to test for vac leaks without a gauge.

When you swap the thermo, I would consider replacing the radiator hoses while in there and putting in the proper coolant if not in the motor.

so was about to replace the thermo, but cant figure out where it is. Any ideas, was hoping to finally get this done over the weekend. any help is appreciated.

Here's the how-to: http://dieselgiant.com/thermostatreplacementandmodif.htm
It's a fairly easy procedure. Just be careful not to over tight the screws. Trust me, you will be in big doo-doo if you do. I did it on my '87 Caddy and now I run without a thermo on that car, until I get enough moolah to get a new intake manifold. Get a torque wrench ($20 at any autozone or your favorite auto parts store) and use it, you don't want to damage the threads in your housing. I don't have the data on the amount of torque needed, but it's just a google search away... :)

take care of the engine not warming up problem first then you should have heat

Get a clean bucket, bowl, or other cantainer that can hold about 1-1/2 to 2 gallons of coolant.

1. With container underneath, use screwdriver to open radiator drain plug. (blue plug on driver bottom)
2. Remove expansion tank cap.
3. Remove tube from airbox to the turbocharger.
4. After drained, use 10mm socket to remove lower bolt on thermostat housing.
5. Remove upper bolt on thermostat housing.
6. Remove thermostat housing from the cylinder head. The housing can stay connected to the hose.
7. Remove thermostat within the housing.
8. Insert new thermostat (there is a notch to make sure it is oriented correctly) and make sure you use a new gasket as it does the sealing between the housing and the head. The round plate with the slots cut in it goes toward the cylinder head. This will restrict coolant flow when the thermostat opens.
9. Install bolts and air tube.
10. Make sure the radiator drain plug is tight.
11. Fill coolant from top radiator hose first into cylinder head and reconnect when full.
12. Fill expansion tank with coolant and replace cap.
13. Have an adult beverage of your choice.

where exactly is the thermostat housing?

side of engine underneath the turbo on right side. its part of the water pump assembly

Yes, same side as the turbo. Follow the lower radiator hose and it will lead right up to it.

It is attached by two 10mm bolts. One on the top and on on the bottom.

ohh ok thank you .
i will try to get this done today.