1988 Pontiac Fiero GT... Just replaced the water pump and had the coolant system bled... Now im leaking extremely badly out of the heater core two days after unfortunately (Steam in the car and pooling out of the car all over the ground near the firewall)..
I have some questions though before I replace it...
What brand is the best brand to get? Napa brand, Advance Auto parts, fiero store, other?? ... I heard some were poor quality and ended up not fitting to incorrect pipe length..
Do I have to re bleed the cooling system or can I some how krimp the coolant hoses when taking them off and prevent any major blurping of the coolant system if any...(taking into account that the heater core needs to be bled)... If I dont krimp the hoses will coolant come pouring out all over the place meaning I have to drain the system?
Also is it possible to bypass the heater core with the two rubber hoses at the firewall and just connect them to a 2 inch pipe of the correct length for now than casually look for a heater core later on..
thanks in advance
------------------ 1988 Pontiac Fiero Gt (fully optioned, factory leather, 5-speed, CJB T-Tops: Black w/ gray interior and blk wheels) 1992 GMC Typhoon #0203 1971Chevorlet Corvette 454cu/ LS5/ 4-speed/ convertible 1993 BMW 850 Ci 6-speed V-12
Also is it possible to bypass the heater core with the two rubber hoses at the firewall and just connect them to a 2 inch pipe of the correct length for now than casually look for a heater core later on..
Yes, bypassing the heater core works fine, however... Just make sure you use a good size (diameter) connection for the two hoses, as a major restriction there will collapse your thermostat.
I had to replace the heater core in my 88 last summer. I went to a local radiator shop that I trust to get one, as I wanted one that was copper or brass, not aluminum. If a new one was not available in copper or brass, I would have had the radiator shop boil out the old one and repair it. They located a new copper one for me that is sold under several different brand names - Vista Pro, Ready-Aire, Proliance. They are all the same heater core being sold under different brand names. The part number is 398203M for cars WITH AIR CONDITIONING and you can get these from Summit ( http://www.summitracing.com...7oorcCFYZaMgodiS4AGg ), Rock Auto ( http://www.rockauto.com/cat...&a=FR2-398203-303531 ), or even Amazon ( http://www.amazon.com/Vista...ity-chart/B004A404Z8 )
Molded heater hoses are not available for the 88s with AC, but Rodney is working on having these made. You will have to buy some straight lengths of heater hose and just bend it to fit. I used Gates Unicoils ( http://www.gates.com/brochu...4961&location_id=541 ) to make the tight bends at the heater core and under the car to the rigid lines.
Yes, bypassing the heater core works fine, however... Just make sure you use a good size (diameter) connection for the two hoses, as a major restriction there will collapse your thermostat.
I have a question about the thermostat bypass - normally the heater core and throttle body heating is a bypass for the thermostat while closed during cold start up: - when the thermostat opens, how is flow maintained through the heater core and throttle body. Is there still enough pressure drop through the thermostat to force some water through the heater? - if one or both of the heater core and throttle body are eliminated, what is the ideal bypass hose diameter to simulate these to allow for sufficient flow when the thermostat is closed, but have enough back pressure to ensure proper flow through the thermostat & radiator for sufficient cooling?
I have a question about the thermostat bypass - normally the heater core and throttle body heating is a bypass for the thermostat while closed during cold start up: - when the thermostat opens, how is flow maintained through the heater core and throttle body. Is there still enough pressure drop through the thermostat to force some water through the heater?
I don't exactly know "how", but through some magical means, the coolant somehow still finds it's way through the heater core.
quote
Originally posted by 88GTS:
- if one or both of the heater core and throttle body are eliminated, what is the ideal bypass hose diameter to simulate these to allow for sufficient flow when the thermostat is closed, but have enough back pressure to ensure proper flow through the thermostat & radiator for sufficient cooling?
The TB heating tube has been completely removed on my GT. It's a non-entity.
I've used a 1/2" copper pipe connector between the two heater core hoses with no resulting problems.
Below is something I previously posted when I did have a problem...
quote
Originally posted by Patrick:
Back in the summertime, my heater core started leaking. I didn't need the heater at the time, so while I was tracking down a new core, I bypassed the leaking heater core by disconnecting the two rubber hoses from the core and re-connecting them to each other. However, between the two hoses I used a fitting which had a very small passageway for the coolant to go through. When I got the new heater core, I flushed out my system and I was very surprised at that time to discover my thermostat looked much like it does in the picture above. I didn't understand at the time what the heck had happened to the thermostat, so I just bent it back into shape and re-installed it. Unknown to me until the cold snap here revealed a problem, the thermostat arms bent again from "normal" water pressure in the system (because the thermostat "arms" were now weak from being previously bent).
So in retrospect it's now easy to figure out what happened. The fitting I used to temporarily connect the two heater hoses to each other restricted the coolant flow way too much and this resulted in higher than normal coolant pressure pushing against the thermostat. The long thermostat "arms" therefore bent.
Lesson learned!
[This message has been edited by Patrick (edited 05-19-2013).]
Hmm makes sense.. Smaller pipe causes increased coolant pressure.. I think i'm just going to wait for the summit heater core to come instead of bypassing it at risk of other components.
Can I use 50/50 (even though it states otherwise in the Ogres cave but only for empty systems) since my radiator is still full and possibly my water pump and lines since the system was just flushed and filled professionally.. I probably will just need to top it off?
------------------ 1988 Pontiac Fiero Gt (fully optioned, factory leather, 5-speed, CJB T-Tops: Black w/ gray interior and blk wheels) 1992 GMC Typhoon #0203 1971Chevorlet Corvette 454cu/ LS5/ 4-speed/ convertible 1993 BMW 850 Ci 6-speed V-12
lateformula mentions several brands of heater cores. I've been conversing with Ready-Aire regarding the heater cores for the Fieros with AC. They are about 1/2 inch shorter than the stock Harrison cores and can't be held in place by the hold down strap at one end and the retainer clip in the housing cover.. I also found Spectra's replacement core to have the same issue. At the moment, I would recommend shying away from their cores and having yours rebuilt, if it's rebuildable. A rebuild is about the same price. Here is a verbatim of an email from Ready-Aire, received today. This came from Customer Service Representative James Coffer.
Quote:
I’ve reviewed the specs for our Fiero heater cores and the part was changed to a higher efficiency design in 2006, which caused us to change the core size. I have asked our parts manager to review the design but with the low rate of actual returns to us from the parts stores I’m doubtful any additional changes will be made. I have to point out that a smaller core can be foamed up to size using open cell foam, if Advance doesn’t have any it’s the same type of foam used for weather stripping.
End Quote.
If you don't have an aerosol can of spray insulation foam, you might try Duct Tape or Gorilla Tape.
For the time being, I would recommend ProRad in Dallas Texas. Their cores are copper like the original Harrisons, and they are of the correct size.
My 1988 GT heater core started to leak in 2023 and I read the comments under “Heater Core Question” which this thread started in year 2013.
Since I didn’t want an aluminum core, I searched for a copper-brass design and finally brought a #98498 ‘Four Seasons’ brand heater core as I have AC.
This core has the CORRECT SIZE of 2.0-inches deep like the original Harrisons heater and manufactured in Mexico.
The core was made by Thermal Solutions Manufacturing, Inc (TSM in Nashville, TN) and the sticker says model 0398203 (FYI - This ‘model’ is the same number of the old Vista-Pro / Ready-Aire cores which were made of aluminum in 2013)
On the shipping label had ‘Four Seasons’ 98498 but also has 94498 (SPI) and 9010186 (APDI) Automotive Parts Distribution International
FYI: Drain, Flush and Refill your coolant at 30,000 mile or 2 years; my original Harrisons heater core nearly lasted 35 years!
And THANK-YOU member ‘RWDPLZ’ for the awesome ‘Fiero Heater Core Replacement’ write-up! My 'AC Equipped Fiero Heater Core Replacement' report from year 2011 was VERY helpful....
Note while can bypass the core w/ plane pipe... you need something to prevent pipe blow out because coolant is lube and most pipes are smooth sufrace and little or nothing for hose and clamp to hold.
Example I made for this it emulates both sizes for the core and that small solder bumps give the hose and clamp to stay on.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
