3400/3500 Swap Information (Page 3/4)
Bridgetown FEB 20, 02:49 PM
I have not blocked off my front tank, however I'm considering it. My stock front tank only has a small amount of fluid in it when the car is cold. As soon as it warms up, it is drawn out. If i fill the front tank up to the proper level, it overflows my rear tank. I have ran my setup for many years like this and I have not had overheating problems. I suspect the front tank can be eliminated, but I'm not much of an expert on how these systems work exactly.
ericjon262 FEB 20, 06:33 PM
I would ditch one tank, it doesn't really make sense to have two unless you need that much volume. then you need to make sure you get all of the air out of it.

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lou_dias FEB 20, 06:37 PM
Perhaps that's been the problem - getting the air out... I'm hoping that the heads haven't warped because I've had to bring it back 3 times for various coolant leaks and the temp light has come on each time...
KaijuSenso FEB 20, 07:07 PM
I'm not sure why you would install an extra coolant expansion tank? If it is only for a rear fill, I installed an inline coolant fill (summit racing) at the highest point of the system on the thermostat side of the engine (drivers side.)
Raydar FEB 20, 11:25 PM
Thanks!
I am happy to see this thread, as I am contemplating a swap to an LZ4 (3.5) or LZ9 (3.9) at some point.
I have another car with an LZE (a flex fuel LZ4) and it's quite quick, even lugging 3400 lbs around, in the form of a G6.
It ought to stroll in a Fiero, with a manual tranny.


quote
Originally posted by lou_dias:

I bought a swapped car (3100 bad head gasket mated to a 4T60-E). I swapped out the 3100 block and heads with a 3400.
It constantly overheats. I believe it is because it is using 2 expansion tanks: the stock 86 Fiero expansion and a setup similar to what has been described here.
There was no mention of blocking off the Fiero expansion tank as a solution in this thread, but is that what is done? My mechanic is suggesting this.



I scrapped the front expansion tank and installed a 20 lb cap on the radiator.
I have a rear fill adapter on my installation (a 4.9 - but that really doesn't matter) and an overflow tank in the rear. It has eliminated all of the cooling issues that I had with my engine. With a 15 lb cap on the rear, all of the overflow happens there. Which is perfect, since it's the high point of the system. No air is introduced.
(Actually, the issue was that the coolant was leaking out of the front overflow due to residue left over from the 4.9 "stop leak" pellets. A "cleaner" system may not have had the issues, but there's no question that what I did works perfectly. I would highly recommend it, if you have room for the reservoir.)

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Raydar
88 Formula IMSA Fastback. 4.9, NVG T550

Praise the Lowered!

Bridgetown FEB 20, 11:33 PM

quote
Originally posted by KaijuSenso:

I'm not sure why you would install an extra coolant expansion tank? If it is only for a rear fill, I installed an inline coolant fill (summit racing) at the highest point of the system on the thermostat side of the engine (drivers side.)



I found these engine difficult to bleed the air from the cooling system. A rear expansion tank seemed to make the process much easier. I suppose a fill port may have done the same. I am planning to try the system with the front overflow removed from the system.
Question, should the rear overflow be plumbed down stream to the thermostat (drivers side) as Raydar suggests, or upstream (passenger side) like mine is?

[This message has been edited by Bridgetown (edited 02-20-2015).]

KaijuSenso FEB 23, 01:29 PM
To avoid worrying anyone thinking about this engine swap, I have never had any issues bleeding my coolant. The in-line coolant fill takes up less space then a relocated expansion tank and isn't necessary if you already have one up front. Note the Fiero stock engines had a coolant fill in the back on the engine because it was higher then the radiator, this is why I added a simple in line fill. I used a regular radiator cap and plugged the overflow nipple because this feature is taken care of on the stock radiator.

The coolant funnel kit is inexpensive and very useful because you can run the engine with the funnel half full and the air will come out and pull more coolant in. Be careful not to run the engine too long because the system won't be pressurized and can boil over, spilling coolant all over (yup I've done this a few times.) Once you're done just plug the funnel to remove without spilling the extra coolant you have and reinstall the "radiator" cap.

Random pictures taken from the web to illustrate, sorry if they go down...




Bridgetown, this is just a thought process but the rear overflow should probably be plumbed to the hot side of the coolant system (driver's side) because this is where the most coolant expansion will take place? The Fiero overflow is attached to the hot side of the radiator correct, the top tank?
ericjon262 FEB 23, 10:15 PM
do you have a P/N for the inline fill? I'm probably going to pick one up later this week for my swap.
KaijuSenso FEB 24, 12:53 PM

quote
Originally posted by ericjon262:

do you have a P/N for the inline fill? I'm probably going to pick one up later this week for my swap.



Sorry no I don't have the P/N on hand and it looks like I didn't put the number in my build thread either (but did say it was a 2.25 inch.)

I'm actually struggling trying to find that size on Summit Racing's website so I'll see if I can find my invoice.
flimbob DEC 18, 09:41 AM
On the 86, there is a heater hose running around the shock tower( shown above ). 87/88's have the heater hose connected to the long coolant tube on the passenger side. Where would one hook up the heater hose located at the trunk side of the motor on an 88?