New car maintenance and overheating

[TheRival]

I know this has been discussed time and time again... i have searched and read as much as possible before posting.

I just purchased this car http://www.r3vlimited.com/board/showthread.php?t=168574 and am looking to do the proper maintenance to get the car to a baseline i feel comfortable with. Currently there is a metal on metal rattle in the top end towards the front cover. sounds like the tensioner is on its way out. (kind of like a timing chain with slack hitting the block although i know the m20 doesn't have a chain) Previous owner stated he never changed the water pump or timing belt in the 3 years / 40K he put on the motor and was unaware of the previous owners maintenance.

With that said, I am noticing that the car appears to be overheating via the stock gauge ( i know they have bad grounds but the gauge does not jump erratically, it slowly climbs). driving on the expressway it will climb to just under 3/4 mark, if in traffic without the heater on, it will raise slightly above the 3/4 mark (never let it get beyond that for fear of mechanical problems). If I turn the heater on full blast at a dead stop, the needle will stay at 3/4 (and yes i have hot air coming out of the heater).

Symptoms i have noticed so far, Top radiator hose is hot, lower is cold. Coolant res is full to the line and looks a healthy green, Most radiator hoses were replaced by previous owner 3 years ago. I cannot bleed the system because the bleeder is rounded (will fix soon). There are no puddles under the car from sitting nor is the cooling system overflowing/boiling.

To Do list:
Check Clutch fan.
Check Thermostat and try removing.
Fix Bleeder.
Bleed.
-See if problem goes away

Round Two To Do List if first is not successful.
-install new water pump (purchased)
-install new tensioner (purchased)
-Install new Thermostat (purchased)
-Install new timing belt (purchased)
-Flush Radiator
-Replace Clutch (if needed)


If i find that the tensioner is not the culprit of the noises in the front end, do you think i have some valve issues? i am planning on readjusting the valves sometime soon but as it stand right now, the car doesn't really hesitate and i have no oil/coolant coming out of the tail pipe.

Also, can a sensor be the causing me problems?

I get the feeling i have a bad pump as the lower radiator hose is cold (how often do thermostats fail?)

anyways, thanks for the time guys (I will keep you updated with my progress)

[strad]

You're going to need a new timing belt, based on mileage, lack of history, and the fact that you're doing a timing belt tensioner.

Check tstat operation by placing it in a pot with a thermometer on the stove. Obviously fix the bleed screw issue, since air lock can cause overheating as well. You might also pull the radiator and have a rad shop flush it for you.

M20 cooling system is pretty simple. This should be an easy one to fix.

[TheRival]

You're going to need a new timing belt, based on mileage, lack of history, and the fact that you're doing a timing belt tensioner.

Check tstat operation by placing it in a pot with a thermometer on the stove. Obviously fix the bleed screw issue, since air lock can cause overheating as well. You might also pull the radiator and have a rad shop flush it for you.

M20 cooling system is pretty simple. This should be an easy one to fix.

Sorry, i purchased the belt as well, forgot to add it to my list!! that would just be silly...

[scottinAZ]

the first round of things should get you back on track. I had similar issues with mine when I purchased it, but did not have the benefit of a working gauge. (cost me a head gasket) once I changed the t-stat, and fan clutch (used new rad, due to damage) the car never went more than a needle width above 1/2 way. timing belt job on these is dead easy, and the tensioner and water pump wont add any to the time that it takes to do the job. good luck on it

edit to say, just replace the t-stat, they arent that expensive, and if you are gonna open the system, you may as well change it and have a better than average chance that it will fix the issue. I think a new one is about 15 bucks or so with gasket.

[TheRival]

Should i be worried about the tensioner at this point in time? can it actually fail? ( i am not positive that this is making the noise) Also when i pull the valve cover, can i reuse the rubber gasket or do i need a new one?

[scottinAZ]

tensioner should be replaced, it isnt that hard, nor that expensive, and it can cost you a motor if it shits. That being said, I didnt change mine when I did the belt. I checked the bearings for wear (if they were rough feeling or sloppy) and when it checked good, let it go at that.

The gasket and half moon things should be changed whenever the cover is removed, the intake draws vacuum on the internal areas of the block for crank case ventilation, any failure of the gaskets to seal WILL turn up as running like shit. not to mention it will leak like a fucking sieve if you dont change the gasket. Trust me on this....

[TheRival]

tensioner should be replaced, it isnt that hard, nor that expensive, and it can cost you a motor if it shits. That being said, I didnt change mine when I did the belt. I checked the bearings for wear (if they were rough feeling or sloppy) and when it checked good, let it go at that.

The gasket and half moon things should be changed whenever the cover is removed, the intake draws vacuum on the internal areas of the block for crank case ventilation, any failure of the gaskets to seal WILL turn up as running like shit. not to mention it will leak like a fucking sieve if you dont change the gasket. Trust me on this....

Great advice, really appreciate it. I usually like to replace when possible but funds are limited and if I can recycle/reuse without harm i will.

I will be sure to grab a new valve cover gasket and half moon. I will be sure to keep the car parked in the mean time while i wait for parts.

[lateracer]

You should do a valve adjustment while you've got everything apart and you're in the neighborhood. While it doesn't really sound like the source of your valves are the source of the noise you're hearing, if you skip adjusting them before you button everything back up and the noise is still there you'll wish you had taken the extra 45 minutes during this job.

A valve adjustment will also give you the opportunity to see/hear/feel the engine cycling slowly. Sometimes it's easier to ID and fix problems when the motor is walking instead of running.

[TheRival]

You should do a valve adjustment while you've got everything apart and you're in the neighborhood. While it doesn't really sound like the source of your valves are the source of the noise you're hearing, if you skip adjusting them before you button everything back up and the noise is still there you'll wish you had taken the extra 45 minutes during this job.

A valve adjustment will also give you the opportunity to see/hear/feel the engine cycling slowly. Sometimes it's easier to ID and fix problems when the motor is walking instead of running.

Yup, just got my best bud on board to help with the overhaul and surprising to me, he has had his hands in the head of an E30 before, so he is looking forward to helping with the project.

the only hard part is Identifying the problem after making so many changes (i realize that if the noises go away its a good thing) but it would be nice to point a finger at a problem.

[jlevie]

Your first round should be:

Replace water pump, thermostat, & bleed screw
Replace timing belt & tensioner (and probably camshaft seal & o-ring)
Flush the cooling system (full flush, not just a coolant change)

The flush and bleed procedure I use is below:

Use of one of the commercial cooling system flush products will do a more
through job of cleaning the cooling system than simply flushing with
water. The process I use is:

1) Drain the old coolant and remove the thermostat. When the thermostat
housing seals with an o-ring I make up a gasket out of pasteboard for a
temporary seal. With the thermostat out you'll have full flow through the
system the entire time the engine is running. Filling an bleeding will be very
quick and easy since the thermostat won't be blocking airflow out of the
block.

2) Add the flush compound and fill the system with water. Bleed per normal
procedure so that you don't have an air bubble in the block. The higher you
have the front of the car (with the rear wheels on the ground) the easier it
is to get to the block drain and the easier it will be to bleed the system. I
like to have the front at least two feet higher than the rears.

3) Run the engine and get it to normal or near normal temperature. In cooler
weather this will require blocking some of the airflow into the
radiator. Generally you need for the engine to be at temperature for at least
15 minutes for the flush compound to do its work. The heater needs to be on
and you want to be sure to not allow the engine to overheat.

4) Shut down and allow the engine to cool to the point that you can keep your
hand on the thermostat housing and cylinder head.

5) Leave the expansion tank cap on and open the block drain. Only a small
amount of liquid will be released because the top of the system is still
sealed. When you loosen the cap the rest will flow out. Doing it this was
reduces the chance of a scald. Once the block is drained put the plug back in
finger tight and drain the radiator. Close the radiator drain when the fluid
is out.

6) Fill the system with hot water and bleed. Then run the engine long enough
to get it up to temperature. That's probably 10-15 minutes. Using hot water
reduces the time required to reach operating temperature and keeps from
having to idle a cold engine over and over.

7) Allow the engine to cool (as in 4 above). Then drain the block and
radiator, catching the fluid so you can see what's coming out of the cooling
system.

8) Repeat the fill & drain sequence until the water coming out is
clear. Depending on how dirty the cooling system was it may take 8-10 cycles to
get to clear water.

9) Re-install the thermostat, properly tighten the drains, fill with coolant,
and bleed the system.


1) Using ramps or a jack get the front of the car 1' or more higher than
the rear. That will make the radiator and bleed screw the highest point
on the engine and facilitate removal of air.

2) With the bleed screw open, add coolant until no more air comes out of
the bleed.

3) Leave the filler cap off, or at least loose, and set the heat for max
temp and fan speed. Leaving the cap loose will prevent air that's still
in the system from causing a "coolant fountain" once the engine heats
up. Start the engine and allow it to warm up to operating temp. As it
warms up occasionally crack the bleed screw to release any air and top
up the coolant as necessary.

4) Once the engine is at temp bring it up to 2000-2500 for a few seconds
several times. Then crack the bleed until no more air is released. At
this point the heater should be throwing lots of hot air, which
indicates that the heater core is filled with coolant. You may have to
repeat this a few times to get all the air out.

5) Drive the car a bit, allow it to cool back down, and recheck the
bleed for air. Over the next few days you may get very small amounts (a
few bubbles) of air out of the bleed screw.