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Finally, after much apprehension, I cranked the Alfa today, and...Viola! It runs as it did before I stupidly changed out the
sender....Since then, I have checked the plugs, made sure the HT leads were connected properly in correct firing order, checked for click & resistance on the TPS, and checked the AFM, Cold start injector & triple checked all connections to
the injectors, + replaced the # 1 injector connection as it looked bad.Now have to reset the idle rpm, and am considering
replacing the thermostat, as the dash gauge still shows 110 deg. F when the engine is completely warm. I don't even yet know where the thermostat is, nor how to change it, but it could not be that difficult; probably need new one + gasket.
Chief Bre 9
 

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well that's good news!
any idea what the solution was, or was it just a combination of a few things you did?

you could buy one of those contactless infrared thermometers (they are cheap these days, 20 $ buys you a simple one.......very useful for other things as well) and aim it at the thermostat when the car is properly hot after a drive.

your 86 will have a thermostat like this, that comes with the housing and gasket O Ring built in.

PN alfa 60522856 (originally made by BEHR)
thermostat housing.jpg

take off basically just two bolts on top and it lifts off, you will lose some water obviously from the top hose.
thermostat.jpg
 

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Hey, thanks a lot for the thermostat pics, and now I know exactly where it is. I really hope that changing it will not result in the troubles I had with the temp sensor! As far as what procedure cured the ills, I'm really not too sure; it probably was a combination of connecting the injector plug to the ECU plug, and of course the backfire was I think caused by having the HT leads on the wrong plug. At least that's what caused the MGB I restored to backfire. I've read several
blogs about stuck thermostats, so perhaps that is the problem. I think to check it, I remove the radiator cap just after starting the engine, and if coolant is flowing when engine cold, it is stuck open.

Chief Bre 9
 

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Hey, thanks a lot for the thermostat pics, and now I know exactly where it is. I really hope that changing it will not result in the troubles I had with the temp sensor! As far as what procedure cured the ills, I'm really not too sure; it probably was a combination of connecting the injector plug to the ECU plug, and of course the backfire was I think caused by having the HT leads on the wrong plug. At least that's what caused the MGB I restored to backfire. I've read several
blogs about stuck thermostats, so perhaps that is the problem. I think to check it, I remove the radiator cap just after starting the engine, and if coolant is flowing when engine cold, it is stuck open.

Chief Bre 9
 

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After your problems (yes I did read your previous thread) I would advice purchasing, or downloading a workshop manual for your car. It is obvious that you would benefit from proper instructions. For example, replacing the thermostat requires bleeding the cooling system. There is a procedure for this. I would also add, if you haven't completely flushed the cooling system recently (in the last 5 years), I would advise doing this, for many reasons. A repair manual will outline the radiator drain plug, the engine block drain plug, the two cooling system bleed ports, etc. Knowledge is good.
 
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Discussion Starter #6
After your problems (yes I did read your previous thread) I would advice purchasing, or downloading a workshop manual for your car. It is obvious that you would benefit from proper instructions. For example, replacing the thermostat requires bleeding the cooling system. There is a procedure for this. I would also add, if you haven't completely flushed the cooling system recently (in the last 5 years), I would advise doing this, for many reasons. A repair manual will outline the radiator drain plug, the engine block drain plug, the two cooling system bleed ports, etc. Knowledge is good.
Thanks, Andy. A factory service manual came with the car, along with a U.S. Road Atlas! However it covered many years so last month I purchased another, more up to date. I have not found yet the procedures for flushing the system, but I plan to take the car to my favorite radiator shop & have the whole thing flushed out. Appreciate you pointing out the two
bleed ports to me, as well as the necessity to bleed the system.

Chief Bre 9
 

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I would advise against taking your Alfa to a “Radiator shop”. Most likely they will have no (correct) knowledge about your car, even though they will tell you that they do. They will then most likely create more problems for you. If you can replace a thermostat, you can drain and refill the cooling system yourself. The hardest part will be removing the 22mm block drain plug. Make certain that you have the proper tools before you begin.
 

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Just keep it simple Chief, for now.....you are basically trying to get the temp gauge to read correct by replacing the thermostat.

you don't need to remove the block drain for that job.....it will be too difficult to get at anyway, without dropping the manifold (it is a real pita to get at otherwise)

so:
turn heater slide up to HOT
Remove top rad hose from the radiator end, that will drain enough water for the job in hand, and then from the thermostat end.
IF coolant looks filthy rusty color, then drain the rest by loosening the lower radiator hose.....but if it looks ok, leave it be!

then remove the 2 bolts securing the thermostat, lift it off.
replace new thermostat
inspect hose is good to be refitted, then refit.
Top up with 50/50 antifreeze mix

run engine..as it gets warm, undo the bleed bolt on top of the plenem and let any air escape (circled in green on photo)
once you are happy, tighten bleed bolt.
There might be another bleed bolt on top of water pump, but you don't need to touch that unless you have drained the whole system, really.

bleed screw.jpg

job done.
 

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Discussion Starter #9
Just keep it simple Chief, for now.....you are basically trying to get the temp gauge to read correct by replacing the thermostat.

you don't need to remove the block drain for that job.....it will be too difficult to get at anyway, without dropping the manifold (it is a real pita to get at otherwise)

so:
turn heater slide up to HOT
Remove top rad hose from the radiator end, that will drain enough water for the job in hand, and then from the thermostat end.
IF coolant looks filthy rusty color, then drain the rest by loosening the lower radiator hose.....but if it looks ok, leave it be!

then remove the 2 bolts securing the thermostat, lift it off.
replace new thermostat
inspect hose is good to be refitted, then refit.
Top up with 50/50 antifreeze mix

run engine..as it gets warm, undo the bleed bolt on top of the plenem and let any air escape (circled in green on photo)
once you are happy, tighten bleed bolt.
There might be another bleed bolt on top of water pump, but you don't need to touch that unless you have drained the whole system, really.

View attachment 1676127

job done.
Wow! If it is that simple, I will do it myself & save some money. It is green in color, just as in the 2-MGBs, a Spitfire,
and an MGTC that I have restored, and I think that color of antifreeze is what all older cars used. Firdstm I am going to crank it & see if the coolant is flowing in a cold engine by looking at the open radiator cap; if the coolant is moving, then the thermostat must be stuck open. I've seen several bogs about this issue, so perhaps that is the real problem,
and I sure should have checked it first and maybe could have then avoided the mess I got into.

Chief Bre 9
 

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Ok Dom, I can appreciate "keeping it simple" as much as anyone. But I also know about deferred maintenance and the problems that it causes. But I will go along with you on this one. Chief Bre 9, go ahead and replace the t-stat and if it fixes your temp problem, EXCELLANT. But keep in mind, if you can't say for certain that the antifreeze was drained and replaced in the last 5 years, do yourself a favor, and do it soon. Many people don't know the internal engine damage that can be caused by old deteriorating antifreeze. Even if it is still green and not freezing, it could be eating away gaskets, aluminum, solder, etc. and you won't realize it until it causes a big $ problem.
 

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Discussion Starter #11
Ok Dom, I can appreciate "keeping it simple" as much as anyone. But I also know about deferred maintenance and the problems that it causes. But I will go along with you on this one. Chief Bre 9, go ahead and replace the t-stat and if it fixes your temp problem, EXCELLANT. But keep in mind, if you can't say for certain that the antifreeze was drained and replaced in the last 5 years, do yourself a favor, and do it soon. Many people don't know the internal engine damage that can be caused by old deteriorating antifreeze. Even if it is still green and not freezing, it could be eating away gaskets, aluminum, solder, etc. and you won't realize it until it causes a big $ problem.
Good advice, and that is what I will do after checking for coolant flow in a few minutes. Also, I have to find a thermostat; my usual suppliers do not have any in stock, so I will keep looking. I also am probably going to replace the water hoses as well.

Chief Bre 9
 

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You will most likely have to buy from an Alfa Parts supplier as you get the t-stat and housing together.
 

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One tidbit of info - be careful/gentle with the bleed screw located on the top of the intake. It is a hollow brass bolt - if you tighten it too much it is possible to break off the flange that provides the seal. I also suggest a 6 point socket to avoid rounding over the corners of the soft brass bolt.
 

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Discussion Starter #15
One tidbit of info - be careful/gentle with the bleed screw located on the top of the intake. It is a hollow brass bolt - if you tighten it too much it is possible to break off the flange that provides the seal. I also suggest a 6 point socket to avoid rounding over the corners of the soft brass bolt.
Thanks for the tip, Eric. I'll also spray some penetrating oil on the bolt. BTW, finding the thermostat in the housing has been a task; both Vick & Centerline are out of stock, but Classic Alfa has them.

Chief Bre 9
 
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