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Discussion Starter · #1 ·
So my 95 LS has been burying the needle for the past week since i got it and i've been trying to verify if it's really getting hot or if it's just an inaccurate gauge. yesterday the light came on too so i think it's really getting hot.

i started going through the cooling system today and doing all the checks. The infrared thermometer shows 225 at the thermostat housing and 165 at the fan switch. when i turn the a/c on, the fan speed does not increase. when i jump the switch, both speeds work. i was checking resistance of the fan switch and the low speed side would intermittently close the circuit but the high speed side never did. Then.....the radiator started puking coolant all over my driveway.

who has radiators right now and once it's in, what checks should i do?
 

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not too sure

first, a 60 F degree delta between top (tstat housing) and rad bottom is pretty extreme. A clogged up rad would explain that tho-- I would replace the rad (valeo 730535 or alternative) and then see what happens-- I doubt you have a fan issue as you describe both speeds do run; BTW the fan only goes to high speed when the high side pressure in the AC system exceeds its threshold -- so turning on AC does not automatically run the fan at high.

I would replace the rad, and then run the car up to temp slowly. Watch the overfill bottle to insure that you have good flow coming in from the throttle body exit.

When was the last time the water pump/tbelt was replaced? Not that I suspect a water pump issue, but always good to know in these kinds of situations -- sometimes the "full monte' of water pump/tstat/tbelt etc is advisable if the tbelt timing is up soon (and the water pump hasnt been replaced in a while!)

let us know what you find radiator-wise--- I don;t have any spares and always like to have one in the parts bin if possible---
 

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Discussion Starter · #3 ·
Of coarse these things only happen on the weekends and i have to wait til monday before i can start searching for a new Rad. The t-belt/thermostat/waterpump is a week old. also replaced all hoses, belts, fluids and filters. I have an extra fan switch and the stove top test shows it's good for both speeds. i will install that when i find a new rad. does anyone have a good voltage/temperature graph for the gauge sender?

also, upon further inspection, found 3 chewed wires up by the windshield that go to the trinary on the motronic side. I wonder if that affects anything on the fan speed side as well? will repair in the morning but cant verify anything until i find a new rad.
 

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1991 164L
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Some cooling issue questions I just had to ask

Was car running hot before new thermostat and water pump installed? You talk like you just got car or do you mean you just got car back on the road after doing water pump replacement?

As for normal operation of cooling fan when system has good low speed resistor installed in upper corner of cooling fan shroud, it only runs on low speed when either a/c high pressure side reaches about 215psi or coolant temp in radiator reaches about 198F.

It only runs on high speed after radiator coolant temp in radiator goes above about 206F.

As you sure that engine block and heads are completely bled of air by venting trapped air out bleeder plug on top of thermostat?

If truly a radiator problem are lower radiator cooling fins by any chance corroded away?

Does radiator fan turn correct way and pull air through radiator into engine compartment?

Sorry for the many questions but some prior history sometimes helps the understand what might be causing problem(s).
 

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Discussion Starter · #5 ·
Yes, Steve. car was running hot before the pump/t-stat were installed. I just bought the car 1 week ago, drove it from where i bought it to where i live w/ no temperature issues as long as i was moving. it was a cooler rainy day w/ a constant speed of 50-70 mph so i had no problems. i did notice the gauge climb a bit high when i was looking at the car, but the pressure in the rad hose never got high and nothing was boiling over. i know the gauges are notoriously incorrect in these cars. next morning i drove the car to work and just as i pulled in, i blew the hose from the t-stat housing to the head. they looked very old and service records show they were over 10 years old. i took that oppurtunity to change everything and properly service the car.

i did bleed the system properly. the fan does kick on low speed. the fins look normal for a 16 year old radiator. there is no excessive corrosion but there was some light blue/white residue along the side tanks of the radiator. either way, the radiator must be replaced because now it's leaking at the bottom of the driver's side tank. GRRRRRR

the wires going to the pressure switch that were snacked upon by a rodent concern me a bit. my understanding is that the switch sends a signal to the high speed side and also the motronic to cut the system out when high revs are requested. is this correct? according to the cardisc, the wires that were chewed are the ones for the motronic.

i have the flow chart for testing the cooling fan circuits but i dont want to check the car w/ a leak. where are the two relays located?

also, has anyone had luck w/ adjustable fan switches or are these just snake oil?
 

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My experience with adjustable fan switch is bad. I bought a '91 164B with an adjustable switch and had overheating problems until I got rid of it. It was in accurate and unreliable. Sometimes it worked, sometimes it didn't.
 

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As for you partial quote from above, "The wires going to the pressure switch that were snacked upon by a rodent concern me a bit. My understanding is that the switch sends a signal to the high speed side and also the motronic to cut the system out when high revs are requested. Is this correct? According to the cardisc, the wires that were chewed are the ones for the motronic.

I have the flow chart for testing the cooling fan circuits but I dont want to check the car w/ a leak. Where are the two relays located?

Also, has anyone had luck w/ adjustable fan switches or are these just snake oil?",
let me say this:


First off nothing in a/c wiring system if Alfa 164s with two speed fan wiring and components if still factory set up turns on high speed cooling fan only low speed RELAY pin 85 is grounded by trinary switch Q20 when a/c high side pressure reaches about 215 psi. Now if low speed resistor has been bypassed then low speed relay runs fan at higher speed but still through low speed circuit relay.

As for other side of trinary pressure switch wiring it is for low or correct Freon pressure reading in system to either prevent compressor clutch from engaging or to let it engage if freon pressure above low threshold.

Yes this side of switch wires do go to both Q66a A/C control panel and motronic S11 ECU to complete logic to energize/engage a/c compressor clutch relay,clutch coil and adjust engine idle speed when A/C on, BUT have nothing to do with engine cooling fan or cutting out clutch when engine revving high.

If you blew one of two short small hoses going to mid thermostat housing and one of the heads, the old thermostat must have be stuck closed or cooling fan didn't come on or as you say one of those hoses was really old.

Were you able to reuse lower housing that bolts to top of water pump with long pipe running between the heads and out the back of the engine?

Radiator for 24v similar to Euro 164s in that both inlet and outlets are in R/H tank closest to alternator as is the thermal switch for grounding low and high speed fan relays.

As for two low and high speed fan relays location, they are under black cover closer to L/H headlight on top radiator support.

Under the other black cover closer to center of radiator are two relays for fuel pump and engine ECU along with fuses for 24v ECU, O2 sensor and fuel pump.

No comment on adjustable fan switches.
 

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Discussion Starter · #8 ·
thanks steve. are there any differences between euro rad and 24v rad? also, i repaired the wires that were damaged and now the fan kicks on low when the engine is running w/ a/c on regardless of temp. i'm gonna look at pressures later when i have gauges. i let it idle in the driveway and the temp gauge went to 220 ish. when i gave it a little throttle the temp dipped down a bit and returned when i let off. interestingly, the circuit never closed for high or low speed switch according to my ohm meter. infrared temp gun only showed 165 when gauge was at it's hottest. i would love to boil that sensor to see if its good or not. either way i think i might have a clogged radiator. i was able to re-use housing after some drilling and tapping. is there a source for new ones? this one makes me nervous.....
 

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Lower 24v housing 00605677260000 Z PUMP HOUSING maybe still available from Di Fatta Brothers - Alfa Romeo and Fiat Parts Sales and Service. that is where I got one for Myron's LS.

They may have 24v radiator either 60579380 or ss number 71735374 or a superceding euro one or an aftermarket one that will work with minor mods.
 

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Discussion Starter · #10 ·
european radiator

What is the difference between the original radiator and a european radiator?
 

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I have no idea

as I say, I got valeo 730535 and it was a drop in replacement

Not sure if that valeo is still available-- let us know what you find out --

Just for giggles, might be worth a trip to a local rad shop and see if they can fabricate one-- dont forget the trans fluid and oil cooler tabs tho
 

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What is the difference between the original radiator and a european radiator?
May not be any differnece or there may not be the two tabs on right side of it to attach 24v engine oil cooler. It could be a bit narrower, too like original 12v radiators but sub frame radiator mounting frame has two sets of holes for radiator rubber mounts and pegs to fit into.

The other thing on one euro radiaotr Difatta had was slight mod needed to attach cooling fan shroud.

Contact them Di Fatta Brothers - Alfa Romeo and Fiat Parts Sales and Service or [email protected] 800-638-7656.

IAP lists 164 radiators, too. Have you talked to Rick at RML in Daytona Beach he may be able to help, too.
 

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Discussion Starter · #13 ·
new radiator ordered from Difatta today and was also able to find lower thermostat to waterpump housing w/ new bolts, seals and gaskets. parts cant get here fast enough. 2 weeks of ownership and less than 4 days of driving. I just wanna drive my car!!!!

can that housing be changed w/o removing the timing covers again?
 

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new radiator ordered from Difatta today and was also able to find lower thermostat to waterpump housing w/ new bolts, seals and gaskets. parts cant get here fast enough. 2 weeks of ownership and less than 4 days of driving. I just wanna drive my car!!!!

can that housing be changed w/o removing the timing covers again?
Not likely and you may have to carefully cut it off outer skin of water housing item 6 second pix from cooling tube item 1 in first pix with dremel tool that goes between heads as it is likely to be corroded to it and tube has two grooves in it for rubber sealing rings itwm 2 in first pix. I hope Ed is ending you those two 14458680 rubber o-rings, too.
 

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Difatta has a 24v radiator. It is a bit thicker than the Valeo and has metal end caps rather than plastic. You have to modify the screw holes at top of fan housing but otherwise it is a good fit and I am happy with the one I just put in my LS.
 

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Discussion Starter · #16 ·
why do we change water pumps w/ timing belts?

ordered a radiator from difatta as well as the lower t-stat housing and had my dad put them in while I was at work this week. old radiator did show signs of clogged tubes. new radiator is really nice. a few minor adjustments and i have a nice new wider, thicker radiator that can be repaired in the future. replaced the housing and was lucky that the pipe behind it wasnt rusty and fragile.

we get it all back together, fill it up, start the car, bleed the system and wait. fan kicks on, and we hear a little squeal. Then........bang!!!! the hub comes off the shaft of the water pump. the brand new water pump from IAP I just put in. i called them up and tried to remain calm. because it was 4:35, they couldnt ship a new one out til monday. the warehouse closes at 4:30. nevermind the fact that i've been on the phone w/ them for 15 minutes. i am in the automotive service industry myself, and if someone came to pickup their car on a friday and something went wrong at the last minute, i would do whatever it took to make them happy. if that means going myself to get a new water pump off the shelf and shipping it out so it gets to the customer next morning, then that's what i would do. considering that was my only demand, i think i was being pretty reasonable. GRRRRRR!!!!
 

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Did the inner hub with serpentine belt pulley bolted to it with three bolts come off bearing shaft of new water pump?

That is very unusual for that to happen especially on a new pump.

As for shipping issue, if UPS truck has left the building on a Friday afternoon, it is pretty hard to ship on a weekend.

Also as for your original question on water pump we pretty much change them on a never been changed 164 at 100K and then every second timing belt change (about 70-75K).

If history of pump and timing belt unknown it is best to change them together soon after you buy a new used 164 to base line your maintenance history.
 

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yeah this one has me confused!

photos would definitely help!
 

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Discussion Starter · #19 ·
yes steve, thats exactly what happened. at first i thought we had forgotten to tighten the pulley bolts, then i saw that the bolts were still there. i will post pics later. The answer to my own question is we change water pumps when we do timing belts so we dont have to take it all apart again before it's time to change the timing belt again.

interestingly enough, i am the 3rd owner of my car. the 2nd owner owned the car for 4 years and did only oil changes. the 1st owner had the vehicle serviced exclusively at algar ferrari in philly. i have the ENTIRE service history of my car!!!! wow!!
 

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The BB2 164S rehab project I am slowly working on now started it's life at Algar too.

I have invoice history from them back into mid 90's.

Your pump hub failure is so unusual. I do have a new spare 24v pump I got from Joey at AWImports in NJ if you get in a bind.
 
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