328 running hot at low speed

Check the fan first...fuse, fan itself, etc.

 

yes, fire it up and let it idle until fans (should) come on. Shouldn't take but a couple minutes from cold or a few minutes after a drive.

 

I have had cars with working fans that run hot when sitting because the fans are not going fast enough. If the fans work but thee car runs cool only when moving, then they are too slow. Check the voltage that is actually at the fans. If it is low, you may need a relay set up to get full voltage again. It is becoming more common as these cars get older.

 

If your temperature is on Celsius, you must have an "Euro" car; the owner's manual for my '89 328s ("Euro" GTB + "Euro" GTS) says:
"coolant temperature should NEVER be allowed to exceed 110°; if it exceeds 110°, you must shut down the engine immediately".
Sorry not being able to make you a better answer, I leave this to the experts, but 120° is too much.

Rgds

 

Ensure that BOTH fans are running.

 

A 328 will always run hotter when standing still than when moving.
The oil cooler is fed by ram air through the port side air scoop.

The two hottest parts of my commute in the DC area were just before shutting down.
Because I had to crawl down three levels in the parking garage at work.
And because I had to drive slowly through narrow streets in the residential neighborhood.


But if your temp is reaching 120C, that's way too much.
Check your thermostat and fans, and check your coolant levels.
(You might want to have your cap pressure checked, as well. I had to replace my tank cap, a few years ago. These cars are decades old, after all.)

Another thing to watch for is the temp gauge periodically "peaking" -- going up for just under a minute and then dropping back (although hotter than normal), with the process repeating. That can be an indication of air in the system --- which often happens if you (or your shop) forgot to open the heater cores when you refilled coolant. When you turn on heat in the fall, you inject air into the cooling system.

 

My fan's only kicks in on a very hot day with the car idling long periods and the temps will goto 90-95 degress C max, with the fan's kicking in it will drop to 80, when I cruise on the highway it will always stay around 80 or a little less like on colder days. When the fan's kicks in you can hear them blowing strong but I can't remember them last kicking in even at slow speeds, never.

I have similar heat here, similar to Texas summer time.

are you sure there is not something else ? when last was water checked or coolant replaced etc?

 

Same here, but the weather is much cooler. Fans kick in at about 95/97° C. Normal standard coolant cruising temp is a tad less than 75° indicated; the numbers marked in figures on a 328 celsius temp gauge are 60 and 90, but there is a red dash in the middle in-between, so that dash is 75° and the needle, when cruising, sets itself just below.
Never heard the fans kick in when the car is rolling, not even at slow speed, only when the car is stopped, for instance waiting at a red light; I do cross the same city regularly, I have 37 red lights on my way, and depending on how many are red, the fans usually kick once or twice during that crossing.
"dinonz308"s car is service by "Brian" it seems, if that "Brian" is Rifledriver, then whatever I might say is of no use, his car is in safe hands.

Rgds

 

328's do not have any issues at all with cooling under even the most adverse conditions IF the system is in good condition. So if it's actually heating as described - temps confirmed, not just inaccurate gauge - something isn't right.

Could be as simple as low coolant level or as complicated as a cracked cylinder block! But most likely it is something easily correctable. FWIW, a bad/improper rad cap will cause the problem...

 

If it was all OK until some work was done to the car, the "usual suspect" is always that the work done to the car has something to do with the 'new' problem. That's not to say that it's 100% that way but it's always the first thing to look at.

 

Also check that the radiator is not obstructed with anything...paper, piece of cloth, etc.

 

One thing you can try is when temperatures begin climbing and you are driving slowly, downshift to increase engine/pump rpm. If this causes your temperature to drop, then the problem could be that your water pump is not putting out sufficient water at low rpm. I have a water cooled Porsche whose water temperature would increase to an uncomfortable level when climbing mountains with rpm at 2000. At 3000 rpm the water temperature would come back to normal. Over the years clearances between impeller and pump housing had increased lowering pumping rate at low rpm. New pump cured the issue.

 

I had the exact same issue many years ago, was a failed water pump in my case.

 

Wow, so much speculation all over the map.

Slow down. First verify that both fans are running and verify that it does indeed start to overheat - but don't let it get to 120 again. If it does you've already got a good mechanic, you don't need crowd of perfect strangers throwing darts at a board blindfolded.

 

Previous comments mention checking the fans are running- get you hands on the fans and see if they turn freely, if getting old they may be tight and not getting up to speed. They will come to a point they will blow the fuses. Also count the fan blades to see you have not lost any.
With the engine and fans running check the inlet and outlet temps of the radiator to ensure a temp drop. Any crap in the rad honeycombe.
With these old fuse boxes, connect a meter to the fan wiring to ensure you do not have reduced volts to the fan motors.

 

Then why bother posting here in the first place.