Question about 1987 Porsche 928

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Radiator over heating problem

When I run my car for about 10 minutes the overflow resovior keeps bubbling up, and the heater indicator needle keeps climbing to hot everytime. I don't know how to bleed the system incase there is an air lock.

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If you hve water bubbleing while engine is running 5 will get you 10 that you have a blown head g asket ,suggest you go to radiator sevice centre,they can pressure test it and also have device to tell you if you have exhaust gas in the coolant. wont take more than 5 min. then you will know exactly where you are at...

Posted on Jul 29, 2009

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You did not say how long have you had this car or how much experience you may have with Porsche (especially the 928) cars. So here are some comments for your consideration based on my experience:
I have had a 1987 928 S4 for a LONG time.
If your car is overheating:
1 - you may have a radiator problem (restricted coolant flow due to "crud" in the radiator. Someone may have put radiator stop leak etc. in it, or poor quality coolant over the years created deposits. - have a radiator shop test the radiator "flow". If someone has put in "normal" coolant and NOT the phosphate free (preferably Porsche coolant) you will develop a problem over time.
2 - your electric fans may not be coming on - you can see this by visual inspection.
3 - the "flaps" in the front of the radiatort may be stuck in "closed position" thus not allowing sufficient air to flow across the radiator.
4 - you may have "stuck" thermostat.
5 - you may need a new water pump - this is probably your problem because they were known to fail especially if the car is NOT driven regularly. Your Porsche dealer service shop OR an independent Porsche service shop should do this for you - it is fairly comlicated procedure. While you are there - change the timing belt and rbuild or change the belt tensioner as well. Then drive the car.
1987 928 S4
1995 928 GTS 5-spd
1999 996 Carrera

Posted on Feb 27, 2009


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98 gmc sonoma heat works of and on

All kinds of things to look at.
Start with coolant level in radiator. Very often if the radiator is low, the heater will not work, or work well, because if there is air in the system, air will rise to the top, leaving the heater core with an air bubble.
Whenever you replace any hose on the car, you must run the engine with the heater on at a medium high RPM (1500 RPM) for a while (5-10minutes) to "burp" the air from the system.
You'll need to make sure the system is full of coolant after that.
Then there could be a partly plugged radiator, a pinched or crimped heater hose, or the heater control might not be allowing the hot water to flow fast.
Be sure to test the temperature of the radiator, to be certain the thermostat is keeping the radiator coolant at near 200 degrees. A thermometer in the top of the radiator will tell you.
If you have a sealed system, you might VERY carefully feel all the hoses to determine the heat inside the radiator after the motor has been running for 10-15 minutes.
Thermostats can get stuck in the "open" position, requiring replacement before you will get heater heat.

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Drained radiator added prestone Radiator flush refilled and started overheating, drained radiator replaced thermostat and now I get no heat from heater,Radiator water is hot

disconnect the heat hoses going into fire wall , put hose into one with pressure and flush as it sounds like it could be bloked in the heater core,the other thing that could be the problem be the hot ,cold switch as it restricts the flow to makes the heater hoter or colder , it might need tlc or replacing as it is manaul not elec

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Air bubbles in the coolant system causing the car to run hot

If you are seeing air bubbles, then the cooling system still has air pockets in it. Loosen the overflow cap and leave it that way for a few days while you drive.Keep the heater turned on at the max heat level. Roll a window down if necessary. Check and top up the overflow bucket daily and top up as necessary. The bubbles should disappear after a few days, then you can tighten the cap. This should also solve your no heat problem. Once the bubbles are gone you can tighten the cap.

If the problem doesn't fix itself in a week, you should have the car looked at for a possible bad head gasket, which would force air into the cooling system. Hope this helps.

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Coolant bubbling out of the overflow

While driving with the heat on you are taking the heat off of the coolant via the heater coil, letting the engine stay a little cooler. You might want to have your radiator cap checked, coolant level and also the flow through the radiator. it could be plugged. take it to your mechanic if you are not comfortable doing this yourself. You can be injured by hot coolant under pressure.

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Just replaced my water pump but my car is overheating. could the water pump be defective?

I would say that is possible, but unlikely, if you just put on new one, this could be most likely your thermostat is stuck or just plain bad. If it is over heating instantly, and your sure your water pump is operating correctly, then it could be the thermostat.

Jun 13, 2011 | BMW 323 Cars & Trucks

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Changed the heater core line. Now there is no heat. What could be the problem

Hi, could there be air in the system from the work done? If yes, recommend you park on an incline, remove the radiator cap, set the heater on high, start the car and let it warm up until there is flow in the radiator. Fill the radiator and keep it full while the engine continues to run. Look for any bleed ports the system may have either in the hoses or at the attach point housings. Crack any bleeders open to allow any air out. Top off the radiator all the way to the neck and make sure there are no bubbles coming up. Bubbles coming out the radiator are an indication of a blown head gasket. If no bubbles, close the cap. Hopefully this will solve the problem.

Jan 09, 2011 | 1991 Chevrolet Cavalier

2 Answers

Heat is not working - coolant was low so filled it.... problem here... heard something about an air pocket

If you dont have an external coolant leak anywhere under your hood that has shown up on your driveway it could be the intake manifold or the headgasket leaking. Also check the thermostate to solve the heat issue.

Jan 05, 2011 | 1998 Pontiac Bonneville

1 Answer

1999 Buick Lesabre heater/defrost blowing cold air but lower vent blows warm air? what could cause this?

You probably have an air bubble and the engine needs to be "burped". I assume you have a 3.8L V6. First take a look in the radiator to make sure it is full. Not just the plastic overflow tank, take the radiator cap off and look. Make sure the engine is cold though. The radiator should be full to the top. The way the system works is that as you drive your car, the water heats up and expands and the check valve in the radiator cap will let the overflow go into the plastic tank when the pressure get over a set amount usually 14-17 lbs. When you shut off your engine, the water will be slowly sucked back into the radiator as the engine cools. If the radiator cap is bad, it may not let the water get sucked back into the radiator and the engine will run hot, you will get air and steam bubbles in the engine, the thermostat will work as long as it has water running by it but if a slug of steam goes by it, it will close. Water will not circulate through the top part of the heater core. "Burping" that engine is a pain but just keep the overflow tank full and check it every time you *start* the car. The air will work itself out. If this does not work it is probably the controls. These are managed by the computer. Try unhooking one of the battery cables and leave it off for at least 20 minutes. When you hook it back up the computers should re-boot. That has solved problems for me with heater, interior lites, power windows, AC, day time running lites, power mirrors, fast idle, rough or slow shifting, CD player, and wipers on GM autos and S-10 PU and Dodge trucks. None of the switches are connected to the device they control anymore. The switch tells the computer to open the window and the computer sends a signal to the window motor. When the computer gets confused strange things will happen or not happen. Things like one headlight stays off etc. I actually had to do it twice on my Bonneville because the first time the AC blower would only work in low and medium. After the second re-boot, everything was fine. Of course you may have to re-set your radio stations.

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1 Answer

My 91 Chevy s 10 Blazer over heats in addition to check gauges light coming on what could be the problem?

There are 4 things you want to check in this order.
1. Make sure your fluid level is up to specifications.
2. Make sure the fluid is travelling through the radiator freely(water pump).
3. Make sure your thermostat is opening. This requires a great deal of caution, leave the radiator cap open (if it has one) and run the engine until the top radiator hose gets hot, If you have no radiator cap, watch for water rising or dropping in the overflow tank.Also watch for bubbles within the overflow or radiator.Also put all temp controls on high on the climate control center and feel for hot air once the engine reaches operating temperature(185-200 degrees). If you don't get heat within the regular time slot of 10-15 minutes you will need a new thermostat.
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Oct 06, 2009 | 1991 Chevrolet S-10

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