I just had a new radiator installed in my 1975 164E and while the radiator was pulled I asked the mechanic if I shouldn't go ahead and replace the water pump while it was out. The car was running slightly hot so that was the reason for the new radiator, I was told. The car still runs slightly hot, the needles goes up to the orange line but never all the way up.

Does this sound like I need a new H20 pump as well? If so, is it a difficult task? I am pretty good with tools and such and think I could do this myself. I am just tired of the high mechanic bills. I have put nearly $5000 into the mechanics for this vehicle in the past two months. I see I can get a H20 pump from IPD for $50 as opposed to the local Volvo dealer who quoted me $315. Thanks everyone
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1975 Volvo 164E - 86,000 original miles!

How are your other gauges? Is the fuel gauge still correct, as in takes about the same distance to start dropping from full? Can be that the voltage regulator in the dash has died, putting 12V on your gauges instead of 10V, causing the gauges to read higher. An easy check is to disconnect the plug at the temp sensor and measure the voltage on the plug. You will be measuring via the gauge, but it does not matter as there is no current flowing and thus no voltage drop. You should measure 10V.

A mechanical voltage regulator that is stuck (burned contacts) can be repaired, but will not last long. Better to replace it.

Have fun...

All the other gauges work fine. The tach operates as it should, the fuel reads fine.

Just before I had a new thermostat installed, the needle always read very low on the gauge. It wasn't until they installed the new thermostat did it start reading hot. Is it possible the thermostat is defective.

One other question...where the heck IS the thermostat? I am not real mechanically inclined which is why I keep mechanics employed. My talents lie in the upholstery and detailing end of it.

Thanks everyone
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1975 Volvo 164E - 86,000 original miles!

There are (used to be) two thermostats at the dealer. I think they are down to only one now, the hotter one. It is only a few degrees warmer than the colder ones and will not make a difference in engine operation. These red blocks are great!
The large radiator hose that goes from the top of the radiator to the front top of the engine? On the engine side is where the thermostat is. You will need to bleed out about 1 quart of coolant before disconnecting the engine side of the hose(2 10mm bolts), otherwise you will get antifreeze all over the front of the motor, frame, and garage floor! When tightening it back up, torque it to about 15-20 lbs, not terribly tight or you will strip the threads in the block.

Easy to do,

Klaus
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98 V70Rawd(108Kmi), 95 854T(88K mi), 75 164E(173K mi)

Looks like your new thermostat is just a higher temp one. Try putting the old one back in and see what happens. Ten to one the temp is back to normal again.

The thermostat is a round brass(?) 'thinghy' that sits in a rubber in the front of the head. It sits right under that aluminium thing (thermostat housing) where the top radiator hose connects to.

Just drain a wee bit of the coolant, undo the hose clamp, take of the hose, undo the two bolts of the aluminium housing, and you'll find the thermostat looking at ya.

cheers, ben


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P131, '65, B20B+M47. P131, '69, B20E+AW71L+LSD. (www.tinustechniek.tk)

I wouldn't put the old thermostat back in, as it sounds like it failed in the open position. Probably the new 'stat is the wrong temp... try one rated for 180F.

From my experience, when the voltage regulator sticks the gauges both peg on full, and burn themselves out in a fairly short period.
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I'm JohnMc, and I approved this message.

My 142E does the same thing -- the temperature gauge always sits at or above the 3/4 mark, whether it's 20 below zero or the 90 degree weather, and I have a new water pump -- never boils over though. I'm not sure what the thermostat is rated at, but whatever it is, I'm going to put one in that is 10 degrees lower, just to see what happens. You could give that a try as well. I'm with the others, leave that pump alone. If you are going on a long trip and don't feel adventurous, take a spare. If they are gonna go bad, they usually give you fair warning. Replacing them is an easy road-side repair. My main reason for saying this that, invariably, whenever I start messing with the water pump I end up with leaks elsewhere, like where the heater supply tube goes into the pump -- even with new seals. Old engines have valuable bits of crud accumulated in strategic locations. My philosophy is to leave them in peace to do their job of keeping that old hunk of iron healthy. ;-)

Sorry. Jumpy trigger finger.

I agree with John. If the pump is not leaking, leave it alone. My gauge also shows slightly hot, at about 10 o'clock. Have the mechanic check the temperature with his infrared tool. Handy. He can point it to the temp sensor to verify the dash reading is correct.
Try to do all the maint yourself. Why pay someone $80-100/hour when you could be buying lots of parts instead?
Klaus
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98 V70Rawd(108Kmi), 95 854T(88K mi), 75 164E(173K mi)

A water pump can't really do much to make the car overheat. It's pretty simple - just a seal, a bearing, and an impeller.

1) The seal could leak, making the system run low on coolant, thus making the car overheat. You'd notice coolant leaking from around the back of the pulley.

2) The bearing can wear out, causing the shaft to wobble, which will lead to the seal leaking and #1. Could also conceivbably seize, stopping the impeller from turning but that would be very obvious.

3) The impeller (pumps water when spun) is pretty foolproof, solid aluminum. I can't imagine one not working, although I have heard of some BMW's that had plastic impellers that could break and instantly cause the car to overheat (warping those pretty aluminum heads too - EX$PEN$IVE!!!), I've never seen or heard of anything remotely similar happening on a Volvo.

What are the symptoms? Does it overheat when sitting still, in stop-and go traffic, or moving extremely slowly? That's an air flow issue.

Does it overheat when driven faster, hard, or on the highway? That's a coolant flow issue - most likely either the thermostat or a clogged radiator.
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I'm JohnMc, and I approved this message.

John, I wish I had been under the hood (like that BBQ cam the BBQ king uses, on public television) when my brother-in-law's 1987 745 overheated last fall: badly warped head, hole in #4 piston...

I later saw that his car's radiator was badly clogged with fuzz -- never cleaned.

And no loss-of-coolant warning system. (Here's the obligatory "See 700/900 FAQs.")

Receipts showed that his mechanic changed the timing belt at 140,000 miles or so, but did NOT change the original coolant pump. (Having spent $4,000 over 3 years with the guy.)

When I cleaned out the car's filthy engine bay I started finding (here's the point!) little steel balls stuck in the goo on the splash pan... Hmmmm. The pump had spilled its guts. Fairly quickly? Dunno. I bet the driver had the radio turned up kinda loud, and he's not particularly mechanically-inclined anyway.

Moral?
When you see the balls it's too late. ;-)
Clean the radiator, once a decade anyway?
Replace the (low-cost) coolant pump when the whole area is bare-naked anyway for timing belt change.
Install a loss-of-coolant warning?
Don't play the radio too loudly? :-)

Thanks John,

It runs hot by just normal driving. I never drive it hard. It is hot in Arizona and I use the AC but it has never gone this high before on any of my 164's so I was concerned. My other 164's always stayed right in the center of the green even when the AC was running.

I have a brand new radiator so I do not think that is the issue. I have a new thermostat as well. I do not see any coolant leaking anywhere. If I let the car idle in the drive for about 5 minutes, the needle goes up to the orange marker.

The car was neglected before I got it so I am wondering if it isn't just a good idea to replace the water pump along with everything else as a preventative thing?
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1975 Volvo 164E - 86,000 original miles!

Won't *hurt* anything, but I'd wager a pretty good sum that the water pump won't change the overheating.

Has it ever actually overheated - i.e. boiled over, had a cloud of steam explode under the hood? It could just be a paranoid gauge.
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I'm JohnMc, and I approved this message.

Hi this is a quick story, (I'm sure everyone has a few).
When I was a kid in college I had a 145. Driving home once my water pump was leaking but I wanted to make it home. I drove it untill the needle went clear off of the red side of the guage and the car just died about 100' from my house. I let it cool down and went back later and poured in fresh water, the car started right up and after changing the water pump drove like nothing had ever happened. I think I had the car for about a year after that incident.
CU