Jump to content
CaddyInfo Cadillac Forum

Stupid Surge Tank Questions


Recommended Posts

1. Is the surge tank pressurized?

2. I have a 98 ETC and there are two visible hoses near the tank at the top - a thin one from the base of the pressure cap, and a thicker metal one that leaves the tank and is attached with a real clamp to a rubber hose that goes up under the engine's beauty cover.

Which of these do I need to verify is clear? Or, do I need to clear the one on the bottom? How hard is it go get to? Remove the tank?

Mechanic put pellets in the surge tank - shall I evacuate it with a vacuum, or just clear the lines?

He showed me the GM pellet package - it says to put the pellets in the "coolant recovery tank" - well - he's not the world's best or smartest mechanic, but he IS honest (I'm his lawyer) and eventually he gets it right.

The car has been running a bit hotter than usual since the coolant change.

THANKS in advance!

Link to comment
Share on other sites

1) Yes

2) You might want to remove the surge tank and flush it out.

The service manual states to install the pellets in the LOWER radiator hose so the fibers get circulated inthe system. It further cautions against installing the pellets in the surge tank.

'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

Link to comment
Share on other sites

On the 4.9, YES, that clear tank is a coolant recovery tank, it is not pressurized, and the cooling system pulls coolant from it when it cools.

On the NS, that is a surge tank that is part of the cooling system, and it IS pressurized, notice that there is no cap on the radiator the pressure cap is on the tank.

As Kevin mentioned I would flush it out, and put the pellets into the lower hose.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Link to comment
Share on other sites

I would not put them in the "recovery tank" on a car so equipped as it has even less flow than the surge tank does, not to mention that the disolved tabs may plug up the radiator cap valve. I'd put them right in the radiator on a car having a radiator cap. The 3/8" line that runs under the beauty cover is the purge line. Pull the lowest hose on the surge tank (if you can get at it) and then stick a garden hose in it to flush it. If you see any "sludge" in the tank, then a shop vac may be in order (assuming you do not remove the tank).

Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...